OOPS POSTED TOO FAST
Don't forget the dremel tool. With a cut off wheel, these are great for cutting metal parts, and the sanding discs and wheels can be a good asset too.
Also a Great Planes hinge slotter, but get the corded model, not the cordless. I got the cordless one first, and could only do 3 cuts before it needed recharged. The corder model works great and makes the tedious job of hinge slot cutting, a simple enjoyable task.
Another great tool is a 5 gallon compressed air tank. I build in the house, and do not have a compressor inside, so I got the airtank with a air gun tool. This works great for dusting off bench, and the model before building. Just dont shoot it full blast into the balsa (oops ). I can keep my tank going for quite a few projects, and when it needs filled just use the compressor I have for car tires, or if I don't want to mess with that, run down to the gas station.
One thing I don't see talked about much is lighting. Good lighting is a must. Get some good overhead flourescent lights for your general lighting, but when it comes to detail, I got a incadescent light with the magnifying glass in it. I paid like $20.00 at hoddy lobby for it, and use it all the time. Its great for getting the detail done.
My next purchase is a drill press. I have gone too long without one, and its driving me crazy. I might get one this week.
OH yeah, and if room is a concern for you, like it is me, Sears sells a 2 gallon shop vac that works great. It is also small enough not to get in the way.

Hope this helps
Jamie