PC sound quality is dependant on speakers/headphones, sound card and whether or not your music is going through the Windows K-mixer, rather than on the program used to play it. That said, foobar2k is the easiest player I know of with which to set up a means of going around the K-mixer, which tends to muddy music up slightly, so it's going to get my vote here. Methods of going around it include ASIO and Kernel Streaming, the latter of which foobar2k natively supports. Afaik no other player supports either without requiring a plugin.