I pretty much just use Audacious on Linux/UNIX these days. I think its a descendant of XMMS, and basically the same user experience as Winamp of old.

The problem I have with most "modern" players is that they seem to want to be a total music library manager, insisting on doing it all based on their interpretation of the metadata in your files. I'm never happy with this experience, so I'd rather something that lets me simply pick music from a directory structure I decided on an organization scheme for.