I'm digging PowerAmp as a player, but if Winamp can really get their desktop sync working (today's app update says it has improved wifi sync), then Winamp FTW.
Oh, and first for all of these "Best of..." threads ;D
all about WinAmp I could go on about the good and bad of all the others I've tried but I really think WinAmp is Androids top player and dare I say Androids iTunes