Nikon lens compatibility
There's a lot of confusion in forums on this subject. I thought perhaps it would be useful to write something about it. People seem to think that they need a DX lens or that only older lenses with a D on it will work with their new D50/D70/D80
Here's the deal:
Any Autofocus lens will work on your digital body!
There's a few sigma lenses that can cause problems under some conditions, Sigma is aware and fixes the problems. There's also lenses made for the pronea serie, labeled as IX. These turn up at very attractive prices on the second hand market but cannot be used on your Nikon dSLR.
Manual focus lenses will work as long as they're Ai.
Non ai lenses can be converted, see http://www.aiconversions.com/ for information. Mounting an unconverted lens can seriously damage your camera.
However, on anything but the D1, D2 and D200 these will not meter. What does that mean to you? It means you're own your own to get your images properly exposed. You can use a hand-held light meter, you can simply guesstimate and use your histogram but you're own your own!
What AI lenses to avoid?
According to my D50 manual the following lenses should be avoided because they can damage your camera.
Some fisheyes: 6mm f/5.6, 8mm f/8, OP 10mm f5.6
ED 180-600mm f/8 (serials 174041-174180)
ED 360-1200mm f.11 (serials 174031-174127)
Anything made for the F3AF
PC 28mm f/4 (serials below 180900)
PC 35 mm f/3.5
1000mm f/11 (serials 142361-143000)
2000mm f/11 (serials 200111-200310)
As you can see a lot of rather exotic lenses on this list. If you have a Thom Hogan ebook (which I can recommend, there's also a table in there of what works and what doesn't. If you're happy enough to own a D200 have a look at http://www.nikonians.org/nikon/d200_and_non-cpu_lenses/index.html