Seems like there are a few Canonites out here, sitting and thinking seriously about that D3.
Come on then Slog........give us the low down on it from a canon users point of view.
I was a Canon user, I havent sold all my gear yet but most likely will.
A friend of mine had a D3, which I was lucky enough to have a play with, I put my own CF card in and took a few shots with a 14-24 at high ISO's and varied apertures and the like. When I got home and had a look at the images more closely I was more than impressed.
During the summer I had to make some hefty decisions.
It was high time for me to invest in a new camera and not another
second hand system, due to increase in workload and upcoming assignments, I was in dire need of a full frame pro body upgrade and since Canon did not currently offer anything that suited my needs as well as a D3, I was limited in my options.
With my Canon set up I managed to use two L series lenses for the bulk of my paid work (24-70 f/2.8 & 70-200 f/2.8 IS and a 10-17mm Tokina for extremeties), so I was more mildy rather than heavily invested anyway, had I had much more Canon glass things would be different.
My camera bodies at that time were are a 30D and a 1DmkI. The 1D is a stunning camera that has given me fantastic results despite occasionally struggling with the dated features, low res, cack ISO but it was bought for only £385 on ebay. Bargain. I loved it!
Most of the portraits on my site are taken with the 1DmkI.
My primary needs are Sports, Landscape, Portraiture and Weddings.
Varied I know but it's all paid work. Emphasis on portraits though.
I aggressively researched all my options with Canon, I had looked at the 1DSmkII's but frame rate, insufficient ISO capability (for my needs) and the unrealistic
second hand asking prices made this option unwise. Plus I really wanted to invest in a new system with a warranty.
A 1DmkIII is a 1.3x crop combined with all the previous AF and sub mirror issues left me to skipping that option and the 1DSmkIII wasn't a good option either for the sports side of things, plus 1DSmkIII was roughly the same price as a D3
with good glass included
and an SB800 ontop!
Many folk talk about the importance of your system meeting your requirements, Canon would basically have had to release a full frame, weather sealed body, that has similar ISO capability as a D3, around 8-9 fps in order for me to invest any further.
I suspect that if they were going to release anything similar in spec, it would be far more than a D3's price tag and unavailble for some time to come.
I couldn't hang around for that, my 1D wasn't going to live for much longer at the rate I was using it.
Even with the release of the 5DmkII at around £2000 to £2500, Canon weren't offering someone like me much of a choice.
I chose to invest in a D3 and a 24-70 with another SB-800 bringing my flash count up to 4 units and basically for the same price as a 1DsmkIII alone and without the select limitations.
Luckily I have alot of friends who don't mind lending me lenses, without them I'd have been in trouble and maybe I would have had to consider more second hand options.
I love my D3 and can't describe in words how much better the ergonomics suit me better than Canon.
I'm not too fond of the way that Canon split the facilities with their bodies, for someone like me it's a repellent. I understand the pro's and con's but it doesn't suit me at all.
Anyhoo, I feel I have written a fair whack of words there, Soz!
but all my gear is Canon (Eos 30D & 50D) + several L lenses, still I'm tempted as it just felt sooooo..... good 
(might find a 1D to play with one day and stay a Canon faithful, but seriously tempted to jump ship?) 
.
:nono::bang:
(passes out)