Is the nikon d60 worth buying?

I'm just wondering on a good first DSLR. I wouldn't mind going for the D3100 or D5100, but still kind of expensive. What else is worth buying used?

Yes - older Nikon models are worth picking up second hand - the D40, D50, D60, D70, D80 or D100 would all be good choices.

Models like the D70, D80 and D100 will have advantages over newer entry level models (like autofocus motors in the camera body, which the D3100 and D5100 don't have) and in the case of the D70 and D80 you also have the Nikon CLS wireless flash control which again entry level newer cameras don't have.

Since prices don't differ all that much I would advice you to look for a gently used D50. You'll have much more used lenses to choose from