Are you looking for a feature rich music player that won't eat your PCs resources? Trout may be the answer.
This is a stripped down audio player. Tracks or folders can be dragged into its window, and playlists can be saved for later use. Trout supports pretty much any format you throw at it (AIFF, AIF, AIFC, MP1, MP2, MP3, OGA, OGG, WAV, MO3, XM, MOD, S3M, IT, MTM) and you can install plugins for the rest if you need. This makes it great as a player you can drag tracks in just to test them. It's much faster and lighter than Windows Media Player and iTunes, as well as accepting more formats.
Trout will also sync with your Last.fm account, so you can continue scrobbling from this little player too. It also uses the freeDB resource for importing Cds, will minimize to the system tray and you can toggle pop-ups with track information. Currently there is no equalizer, although this is planned for later versions, and it doesn't feature any library management. Despite that, it's a great little flexible player that you can run without using too much processor power.
Trout is one of the best small audio players available, don't expect flashy graphical interfaces, just a basic application that works perfectly.