My fav is 1by1. It's simple, handles Winamp plugins and doesn't gobble tons of memory. http://www.mpesch3.de/

I downloaded iTunes recently ..
The good : Radio feature is great, you get tons of stations and stuff. The visualizer is neat too. Fun to stare at. The library system is neat, if you can sort all your MP3s well enough.
The bad : Having to make playlists just to copy songs to the iPod is annoying as hell. Why can't I just drag-drop tracks right onto it, and it makes a playlist automatically? It only plays MP3s and Apple's format. No OGG, MPC, APE, CUE support .. what gives? It also takes up 45 MB of memory. Maybe this is justified by having so many features, but probabally not. :P I managed to crash it twice, just using it. Naughty!