don't get a d100, it's totally outdated and discontinued now. The d70 is even slightly better than the D100 in a few points, where it'd be a better idea to get a used D70s. The price for the D100's aren't worth it at all right now.
They are good cameras though, so if you have a great opportunity, go for it, but you'll have just as good of time using a D70s. So if you're actively looking for a D100, I'd say look for a D70s instead. Probably save a bit too. Otherwise I"d recommend the D80 which is basically a D200 without a ton of fluff (fluff which very few people would every use/ know how to use / have the $$ for equipment to actually use).