I guess it would depend on which purpose its for.
If it were for going to the range I'd truly like to have a 639 with a good custom barrel, trigger job and some really good sights. I love the feel of the 39 and I'd actually do one up but I think it would be ridiculously expensive since the barrel would be a one off custom proposition.
I suppose almost as good would be a 952, should definitely have bought one of those when they were around.
For carry its a little different. I'm not sure that the M&P .45 Compact isn't a pretty darned good contender although I'm pretty enamored of the tsw 4513 I picked up recently.