There's also http://aimp2.us/, which, AFAIR, in some respects whips Winamp's ass. Sadly nothing comparable to either on Linux.

Maybe its because I don't know what I'm missing, but I didn't start using Winamp until version 5, and I think its great. Sure it has a lot of unnecessary or even broken features (looking at you audio converter), but those are easy to ignore and you can even remove some of them.