It's really personal preference, but there can be some things to lean you one way or another.

If you use an iPod, you'd probably be best served by using iTunes for your music management. On the same note, if you're using a Plays for Sure player (like a Sansa) then you'll want to use Windows Media Player. Zune users should use the Zune suite, etc.

If you're not bound to a player, then you can use whatever you like best. It still may be iTunes, may be Real Player, may be Win Amp. Heck, you could try a bunch of them and see which you like best.

Personally, I use Windows Media Player since it plays nice with my Sansa and integrates tightly with Windows Media Center.

Mind Over Matt'er - Technology musings, opinion, and more straight from TechLore's head geek.