Blimey, I didn't think anyone took much notice of my ramblings about food photography. I've got a lot to live up to after that rather nice introduction by fabs and Tim!
Looking through your blog, KG, it seems like you are taking this whole thing quite seriously so I'm going to assume that you want to take the photography equally as seriously. And for that you're going to need to make a hefty investment - but luckily more in time than money, although you could spend as freely as you wanted to.
The first thing you're going to want to do is look at lighting and the good news there is that the best lighting for good food photography is free! As Tim has already mentioned, natural light really is the best and we're rapidly approaching that time of year where you've got plenty of it to work with. All you really need is a suitable room (or selection of rooms), something to diffuse the light, a load of reflectors and about five pairs of hands to hold them all. Or you can just get creative with lighting stands, blu-tack, etc. But the look that works best for me relies on a single large light source (the windows) and light being bounced back into the subject from every angle.
If at all possible I like to shoot in my lounge and at this time of year that gives me a working window of between 10am and roughly 4pm. I'm fortunate enough that it's south-facing and has a massive set of French windows at the end which allows loads of light to spill in and bounce around the room so it's really practical all-year-round Unfortunately the walls aren't quite the right colour, being a light-ish yellow, but I've got creative with white foam-core in the vital areas rather than redecorating. I also employ a large (2m²) diffuser to cover the window and soften the light and sometimes double-up when it's a really bright day or use a single thinner diffuser when it's slightly overcast but still too bright.
General rule of thumb for me is if you can put a shiny white plate in the sunlight and you're getting harsh reflections and dark shadows then it's time to get the diffuser(s) out. I've got a couple of really shiny dinner plates that don't see much use for my work but serve well as test subjects - try and track down at least one on your travels as it's a great help. Want to know what the best thing is? The cheapest and nastiest glazes are generally the best for testing so there's no need to spend a fortune on expensive china.
In terms of bouncing light around, I'll use whatever I can get my hands on, but I tend to favour white foam-core card. You can pick it up from your local craft supply store at a reasonable price, but it does get 'better' the more you pay. I tend to work with sizes from A3 up to A0 and try to buy the best stuff I can find as I've noticed the thinner 'cheap' stuff tends to start yellowing a lot quicker - and you don't want to be bouncing yellow-ish light around! Either way, store your card somewhere dark and try to keep it as spotless as possible.
If you really can't shoot during the optimum conditions or your 'studio' doesn't allow for decent light, you'll need to fake it. I find the most effective approach to be of trying to recreate the large single light source using artificial light so for that you'll need one (or more) large light sources. For me that means lights with big softboxes (I use Speedlites with Lastolite's 60cm Ezybox Hotshoe) and the same selection of reflectors and diffusers to recreate that 'flood' of light you get from the optimum natural lighting conditions. It all sounds simple and to be fair it's quite a simple theory but the method takes a lot of experimenting with to get right.
The benefit of using a system like the Speedlite/Ezybox Hotshoe combo is that it's incredibly portable and easy to set up on location or in conditions where you wouldn't necessarily get a set of studio lights in or even to. The downside is that it's an expensive way of doing things as you'll probably have to throw in some form of remote triggering (not sure what the equivalent of the ST-E2 is for Nikon users) or run the risk of cabling it all together.
Once you've got the lighting sorted and you're confident you can recreate your 'look' in various locations you can then start to worry about the equipment you're shooting with. The first bit of kit I'd recommend would be a sturdy tripod that's easy to position and a suitable head (I like geared three-way heads for fine adjustments) for the sort of work you'll be doing. If you'll be doing a lot of work in a studio then you might consider a camera stand, but that would be far too heavy to transport around so a decent tripod and head would probably make for a good long-term investment.
With regards to the body you are shooting with, I have to admit to having zero knowledge of Nikon cameras although from looking at the specifications it seems fine to me, especially if your output is mostly web-based at present. In reality it will be the glass on the front as much as the subject matter in front of you that will determine just how good your shots are but when you upgrade I'd highly recommend a camera with Live View functionality.
Now, to the glass. And here's where the problems start. I shoot with a 5D and
Canon's TS-E 90mm f/2.8 tilt/shift lens. For me it's the perfect combination and I'd recommend any food photographer do the same. You get an amazingly sharp lens, excellent background blur, great contrast, an extremely usable focal length and minimum focus distance and the amazing creative control that a tilt/shift lens gives you.
Unfortunately you are a Nikon user and while I'd like to recommend their
85mm f/2.8 PC-E I've found their
24mm PC-E a tricky lens to get on with and from what I've read the 85mm will be more of the same. It just doesn't seem to function in the same way as the Canon and I find that incredibly frustrating. It doesn't even fit properly on some bodies! And let's face it - if you've bought a D60 you're hardly likely to be spending somewhere in the region of £1,300 on a lens alone.
So If I was going to buy a brand-new lens for food photography, I'd be spending my pennies on Canon's
50mm f/1.2L or even the
50mm f/1.4. Both would make for an extremely usable lens on either a full-frame or a crop-sensor body and would give you the results you'd be looking for. Unfortunately I don't really know Nikon's range that well so I'd guess that you'd be wanting one of their
50mm line-up although I couldn't tell you which one was the best. Perhaps even
Sigma's Nikon-fit 50mm might work.