It seems that for <$400, the Letus35 is the adapter to have (I have a Canon GL2.)

I have some questions though.

Should I go for the Canon FD or Nikon AI mount?
What should I look for in a lens to buy for it?

I was thinking of just starting with a 50mm f/1.4 non-zoom lens since they are pretty cheap. However, I am new to lenses and I don't know what I need, or what to look for in a lens. Some guidance or suggestions would be helpful.

Thanks