The 28/2.0 is nice if you can afford it (around $150), and the 28/2.8 is really cheap and more than adequate.

The 35/2.0 is a really outstanding lens. I have the latest version. There is an early chrome nose version with a concave front element that is considered very desirable for B&W shooting (sometimes the radioactive front element can be discolored from age, so it's not usually recommended for color), but collectors have jacked up the price.