a timely question, as I've settled on the 35/1.4 and 105/1.8 AIS lenses for my long and wide, but am looking for a 50 I can be happy with on my F5. I just sold a 50/1.2 AIS as the rendering just didn't gel with me as a 'normal', and now I've got a 50/1.8 AF-D. Enjoying autofocus much (but not all!) of the time, tentatively satisfied but not thrilled with rendering on film.
My current thoughts for a happy 50 are with a a Nikon 50.1/8 AFS-G, or a converted Summicron-M 50. Af with immediate override is tempting, and the classic Summicron look for a normal lens is as well.
That said...... if I could adapt any, let's got pipe-dream here, something I can't afford. Definitely a Summilux. The mount adapters are stop down metering only as I recall, so best with something truly unique that just HAPPENS to be nice to shoot wide open.