You don't say what lenses you have at the moment so an upgrade/change of lenses may be all you need to give your pictures a bit more oomph.
In your spare time why not move away from digital and pick up some old film stuff or try a bit of lomography.
The thing is, I want my weekend enjoyment of photography to serve as 'enjoyable training' for my pro-shooting, but my problem with film (and I own a spotmatic and a zenit E) is that I want instant results (so I can improve quicker) and really I need something that is both enjoyable and I can justify owning professionally, as I understand it clients won't pay more for 35mm film, so there is no point shooting film- I do enjoy taking the spotmatic out, but I always am left thinking that the development costs could be better spent elsewhere, I have access to a darkroom- but I have neither the time nor the desire to process my own film, it probably seems i'm giving out mixed messages here (and I probably am), but I don't want to be one of these niche art photographers who only shoots on film and only drinks tea in one particular cafe in shoreditch- I want to have pro-grade kit, but use it like an artist, I think the heft of the 1d gets in the way of my creativity.
I think a leica would fit the bill as a viable second body to an SLR as rangefinder design lends itself to higher quality (non retrofocus) wide angle lenses so a m9 with wide angles and a 50 (for street shooting, and studio wide angle), and a 5d with tele, macro, 85L and all the things the leica can't do
a film camera is also not really any smaller than a 5d
the lenses I have (and have had) are:
sigma 15-30 (so so poor, even compared to the 17-40 which gets a terrible rep, i'll post up some pics when I get back to my laptop- if you thought the 17-40 had bad IQ at the image borders...) Sold
manual focus 28mm macro (fun to use for it's close focus and tiny, but difficult to focus properly without live view, a 5d viewdfinder with a faster screen could help here- also not really very sharp until f4) Still own this one
sigma 28mm 1.8 macro (super sharp at f2.8, and focusses to 1" in front of the lens- actually I want to get this lens again, shame it's so big and has poor af- great manual focus feel though, very long throw) Sold but want it back
canon 50mm 1.8/1.4- broke the 1.8, fixed it and gave it away, fixed another one for a friend, so poorly made I could never wish for another. The 50mm 1.4 is sharp enough wide open (on a good copy) but feels rubbish to manual focus (which is no good for video, and also just feels no fun), weird outlining to the bokeh, and has that canon dullness that I am beginning to hate. Sold both of them
takumar 50mm 1.4- lovely feel and a joy to use, but wasn't all that sharp at 2.8, the canon lens beat it. A 5d and ee-s would have helped nail focus as I got a very low number of keepers. Slightly yellow (due to yellowing of lens elements due to radioactive coatings on the lens

) but had very nice bokeh. Sold
pentax 50mm 1.7- so so sharp at 2.8, soft at 1.7, tiny, but has very rough bokeh when stopped down due to 7 bladed apperture. Sold
helios 44 58mm- crazy lens, feels like a piece of russian crap though- and i'm not crazy about the 58mm focal length. I also hate the way the apperture works so this never gets used. Worth about £4 so sits on a zenit E I have on display somewhere
canon 85mm- sharp, good bokeh, small, light, ok build quality- what's the issue? It's boring and I get uninspiring images from it- find it a bit long on a 1.3 crop too. Minimum focus distance is too long so pretty much strictly for portraits or for larger product shots. Wicked CA until about f2.5. Still own it
tamron 90mm- the sharpest lens I have ever shot, at f2.8 it is as sharp as it gets- shoddy construction, annoying 'push-pull' AF/MF, noisy/slow/poor in low light AF. Sold, but I do miss it, sharper than the canon
canon 100mm- a much more useable lens than the tamron, great AF. Horrible bokeh when stopped down. Sold, considering the 100mm L or the 100mm zeiss + MPE-65
zeiss 135mm f3.5- a bit slow, but sharp edge to edge, tiny, and fun- just wish it was f2.8. Still own this.
Tair 11a 135mm f2.8- at 2.8 even sharper than the zeiss at f4, 20 bladed aperture, but huge, heavy and a russian piece of crap

. Sold
mayer optik orestor 135mm f2.8 preset- awful looking 'zebra' lens, not sharp, not deserving of it's reputation as the 'bokeh monster', not very smooth to use- the tair is a better lens, and better made. Sold
Had a few other 135mm lenses too, but nothing worth writing about as most of them sucked
sigma 150mm macro- nice lens- nearly as sharp as the canon, but horrible to use, ugly, not very good as a tele lens, heavy, poor AF, and a bit long (making depth of field very tricky). I used to shoot a lot of macro with the 100mm, but I sold it for the 85- now I never use the 150. It will likely be sold
so I don't really have many lenses left, only 2 canon mount and I want to get rid of both of them. A 17-40, a fast 50 (probably zeiss or sigma) and a new macro (again likely zeiss, but I wish it did 1:1 so likely the 100L) will probably give me the buzz I need, a sharp wide angle prime might be nice too
i've never shot the 17-40 on full frame so corner sharpness does concern me as I never saw much of an issue on a 1.3 crop but I really need the width as I shoot hotel interiors and I prefer not to do panorama's
I shot the 12-24 and it was a terrible lens...I think the sigma 8-16 on a crop camera could deliver better results
I also have access to a d300 (my dad's), but I hate the weight of the camera, the ergonomics, menu, implimentation of live view, and the 18-200 f5.6 lens
I had Canon gear and some of their best glass (85mm f/1.2 II, 300mm f/2.8 IS etc) and Nikon gear and some of their best glass (70-200 VR II, 135mm f/2 DC etc) and got rid of all that and now have just the M9 + 50mm f/2 Summicron. It's far more fun to carry and shoot with the M9.
Like you I felt the DSLR + lenses was too big, too heavy and too intrusive. It was fun sometimes to swan about with the big lens on and people getting out of your way, but I prefer going unnoticed.
It depends on your budget, but you could always look into a Leica M8 + 28mm, a Fuji X100 or if you want wide angle primes a Zeiss 21mm for the Canon gets very good reviews and I've seen some stunning pictures from it. You did say you had the 85mm f/1.8, but the 85L is in a different league to the 1.8 and a great piece of glass.
The 85L is a definite option, but i'm just not set on the 85mm focal length (but if I change to a full frame cam then i'll have to forget everything I know) the minimum focus distance restricts it's use to portrait only imo, where as I think the zeiss 100mm could do double duty as portrait and product, and I don't do enough portraits (and likely not at f1.2) to justify the cost. It is also so huge and so heavy, and perhaps a 90mm summicron on a leica would be a better option than the 85L- i'd really need to have a serious think about where i'd like to put my entire life savings, i've only ever seen a leica from across the street, I might hate it for all I know. What is it about the 85L that puts it in a 'different league'- colour, bokeh and speed?
Sorry about the 645D, I thought you were minted

Won't mention the Leica S2 then, though you'd have to be totally mad and minted for that.
Other possibilities. 5D2 with a couple fast primes, even fast manual focus primes (change focusing screen) to satisfy that masochistic side

Fabulous quality, and would go very nicely with a Fuji X100.
Leica M8

and Pentax K-5

:nono:
oh no no i'm definitely not minted, i'm technically still a student...
this is my entire student loan at stake here, aha
Hmmm. Boredom seems to be the factor, we all suffer from time to time.
I find that AF is much faster than MF and that just could matter in some situations as although great critical focus isn't really required (IMVHO) in many images these days we pixel peep and expect everything to be extra sharp so speed matters if your subject is likely to move.
Personally I don't agree with Canon kit being too clinical and lacking in character. IMVHO it's just modern, well dsigned kit. A few minutes craping some paint off the body with an old dinner knife and a smear of vaseline on the lens should give you the character you're looking for
How about a MFT? A used G? or GH? and a few manual lenses or better still only one lens, Leica or Zeis if you like, might inspire you without emptying your bank account.
I have toyed with the thought of a m4/3, as it might be nice to work with a full frame and a 2xcrop, as the same lens would have a totally different purpose, and a gh2 would be very useful for film-making (if only canon lenses weren't electronically controlled

) I'd really have to play with a 4/3 camera more to see how i'd get on with an EVF
Doesn't look like any one else has pointed it out but you could get an adapter and use the pentax m42 on your nice camera...
At least short term then see whether it'd be better on the slr?
But sounds like you'd prefer the m9 or just going back to manual film...
I like my m42 28mm f2.5. No where near top notch glass, but when you get the shot in focus - such a feeling.... doesn't come very often tho :/
Anyway - just a thought, you then still get to keep the nice camera and mp yet use the older lenses...
I do use m42, and pentax lenses on my canon, but I sold most of them off to pay for canon AF gear. The more I think about it the more I think it's the camera at fault for making me un-inspired rather than the lens.
If you do high enough level commercial work to justify invoicing your clients for equipment hire such as DMF then I'd seriously consider it as an option. Buy a camera for personal work, something you love to shoot with, and just use DMF as and when you need the quality and image size.
Alternatively, you can get a mint condition Hasselblad H3DII-31 for approx £3500 from procentre most of the time in their 2nd hand dept. So sack off your canon gear to cover it?
I do think there's a definite possibility of this happening, leica m9 and a h3d (hello lottery

), but also a part of me wants to have one camera (or at least one crop factor) which I love to shoot with and get to know inside out as I shoot with it as much as possible so I can visualise the shot before having to get the camera out, to shoot instinctively with the camera as an extension of my brain. I learnt to do this with the pentax, but swithcing to a different crop factor threw me off (they say it takes 6 months to re-learn) and the fact the camera rarely comes out with me means i'm just not learning to shoot. I think I have to make the choice about whether I'm going to shoot with just primes (where it would be more beneficial to have a consistant crop factor across multiple cameras), or use zooms on one of the cameras, where it wouldn't be so much of an issue if I was too close/far away
I don't think i'm at the invoice stage yet, i'm very much at the tipping point of where the equipment I buy will dictate where I go as a photographer. I.e. studio or field. The course I'm doing at university is 'interactive product and service' design, and although not related to photography- it is very much related to advertising and is highly commercial, so I have found myself a lot of oppertunities to shoot product photography or to shoot ad campaigns which actually ended up going to press as most of the projects we are set are with a live client, it was really an unexpected (but mutual) bonus for the client to get a high quality campaign at a student price. But this whole experience has brought to light some issues with my current SLR as it is neither a studio quality camera, nor a walkabout camera, and I have no desire to be an event/sports photographer so i'm just not sure it's the right camera for me- although I do often get asked to shoot gigs/events/sports so the camera does see use there, enough to justify it over a 5dmk2, perhaps not...
at present I do make money from photography, but it is not full time- and i'm not even sure it's a career I really want to go into as a freelancer, I imagine that my skills and equipment would be beneficial to me as a designer as I could hold the position of in-house photographer/documentor which would likely be a valuable asset for a smaller company, maybe they would have access to medium format digital's I could borrow for studio work, but if they can afford to have MFD i'm sure they can afford to contract a pro, I really don't know- further research is required...
Basically I'm in a position where I have enough to buy the right tool for the job, I just need to figure out what that job is- and I don't want to make the wrong decision and have to work for years to be able to rectify my mistake
I am trying to avoid owning anything which only has one function as it would be difficult to justify to myself and my financial advisers (my parents...)
also it should probably be noted (as if you couldn't tell), that I am an aesthetic driven hipster who enjoys to look at and use beautiful objects- my justification for this is that it is my job to design and create things for people to enjoy and use, so I wish for my life to be stuffed full of enjoyable things. I dress sharply (bespoke suit, hermes tie) everyday as an aesthetic choice, you will rarely see me using anything for the sake of it, i'm not the kind of person to wear jeans and a t shirt and buy things that are on 'special offer', i'm the opposite of my bargain hunter pragmatic father and i'm not exactly your typical topman wearing, 550d sporting 'student' either (although I do love rice and beans...), so I think a commitment to luxury as opposed to nessescity is what defines me as a designer, as a photographer, and as a person. I make large, defining purchases with the long game in mind, 10 years from now when the leica is beyond obselete, it will still function as a sculptural object and as a source of inspiration for me as a designer.
I think it's clear that the 1d just has to go to be replaced by at least a 5d for now- but the build quality and AF of the 1d really do make me want to keep it! From my perspective as an aesthete it also looks very very cool I do have to say
I'm sorry this has turned into such a monster of a post