Winamp 2.91 here.
Still use it - have no reason to 'upgrade'.
I've grown on the interface, and I don't need any extra 'buttons' or such - just confuses me. Even with different skins, I know exactly where everything is.
I still haven't had the problems with the 1000+ files, but that might be a feature of 2.91.
My favorite part, the part that Really has kept me from upgrading, is the minimalistic resources that it uses. Plain and simple. I like to keep it running in the background while my AXP 2100+ runs whatever game I want, so I can't afford to have Media Player or iTunes running.