Winamp has long since been a favorite for playing mp3's.
This isn't going to be a long drawn out post... just bringing to your attention a great lightweight mp3 player in Winamp Lite (scroll down to see the link to download).
Super fast load times, good and simple interface.. its really the classic winamp that I fell in love with many years ago. I suggest not installing the winamp agent, I see no reason for it to run constantly just to speed up the load time a bit when I want to play an mp3... especially since Winamp Lite loads lightning fast anyway - about as fast as notepad!
Here's the link again