I've been a loyal user of WinAmp for several years. I am a big fan of skins and my favorite is currently MMD3. However I recently got tired of using the file system to navigate my music collection and sought out a change. I'd tried iTunes in the past but was underwhelmed by its lack of skinning functionality.
In the past few weeks I've given iTunes another shot and it is now my favorite player. It has a few elegant features that make it a killer app for organizing your music. The UI for navigating your music selection is straightforward and reminiscent of the iPod's. I also like the the built in playlists like 'Recently Played', 'My Top Rated' and 'Top 25 Most Played'.
The only downsides have been that I've had to update ID3 tags for my MP3s to get the most out of the music library UI and I miss some of the killer visualizations in WinAmp skins like MMD3. However this won't stop me from relegating WinAmp to the back burner and making iTunes my music player of choice.