I discovered today LongPlayer, a standalone application, pluggable with Winamp and XMMS. This application monitors what you are listening to, allows you to rate the music, and to build custom playlists. Since it records what you are listening to and when, LongPlayer is able to feed Winamp or XMMS with songs you haven't heard too often in the past and that you like the most.

I like the concept, so I give it a try with my small collection of MP3, 1GB ripped from my CDs for which I feel I can need to listen to them at any random time. I'll see next week if the concept works.