Ok iTunes gets a lot of flack and I don't know why. I don't like Apple Products other than the iPod. I could rant on how terrible Apple is but I won't.
iTunes however is something they have done right. It has a clean interface, it doesn't use a lot of memory, and it's just simple.
So why would I use any other media player? Windows Media Player is awful in my opinion. I haven't used Winamp since 2004. I never liked Winamp's interface.
So is there a reason to switch? I keep my music very organized. All high quality, all album art, and proper tags.