There isn't one Nikon 50mm that does everything best.
But I would argue that the "best" all-around every-day performance will be from the 50mm f/1.8 AI.
The best in terms of wide open performance is probably the 58mm Noct-Nikkor, but I cannot confirm that with personal experience. I've never even seen one in person, let alone shot with one.
The best at the wider aperture settings just down from wide open (f/1.4 to f/2.0) is probably the 50mm f/1.2 AI-S.
The best in terms of bang for the buck is probably the 50mm Series E. They are pretty much up there with the AI 1.8's in terms of performance, but they are as cheap as dirt.
The only one that really isn't the "best" at anything is the 50mm f/1.4. But even then, it is a very good lens that I would have no qualms about using. I love my pre-AI one.
So, IMHO the only way you can "go wrong" is by spending waaay too much money for the Noct-Nikkor. Sorry, but no 35mm camera standard lens is worth that much money.
My advice is to buy one that comes on a body. That way you save money, and you get a backup body. I got my Series E mounted on a very nice Nikon FG for $65 through the APUG classifieds.