I'll put in a vote for the 28mm f/2.8 AiS, which was pretty firmly attached to my FM2 in the old days and still gets occasional use. Very versatile - sharp, focuses close, great macro lens reversed, good on DX digital, still quite usable on FX except in the far corners. By chance a local store here has a lot of the lenses mentioned above for price comparisons. They're asking $179 for the 28/2.8 AiS, $179 for the 24/2.8 Ai and AiS, $229 for the 24/2 AiS, $89 for the 28/3.5 Ai, $199 for a non-Ai 24/2.8 NPK and $177.31 for the 25-50/4. I'm not sure what condition these are in, but the comparison with KEH prices may help you decide whether it's worth waiting for something to turn up second-hand nearby.
Cheers, John