If OP wants manual focus lens, I'd exclude the current 50mm f/1.8D. I have one and focusing this thing manually is not pleasurable. It's focus ring is not dampened so it feels loose and somewhat twitchy. It doesn't have the oily smooth feel of the lens made for manual focusing. It works but not something I enjoy doing.

We had a rush of what is the "best" <insert product here> threads. I really wish people define what they mean by best and the parameters associated with it. A lot of things in photography is subjective. Price and availability varies quite a bit, too. Without knowing what OP is looking for, it's rather difficult to make recommendations.