I shoot mainly black and white, and I love the 50mm focal length. I shot with this lens exclusively for a solid year and like it a lot. It doesn't exude physical quality, but it's light and cheap, with low distortion, and is plenty sharp. Some say it has low contrast wide open, but I have mostly used it in combination with fast, contrasty film stocks, and so have no reservations about shooting at f2 any time, all the time (handheld people photography). Also, I find the AF to be fast (in comparison with the 20mm f2.8 afd and the 85mm f1.8 afd), at least on the F6.
For $100, just buy one.