I've been using the same skin for Winamp since like 1998 when they added support and I found the skin. When they switched to v3, I stuck with v2 and when they got v5, I've been using it as v2 all these years. They have improved in some key areas, but most of them I don't use.
The plug in library for Winamp is amazing though. You can find pretty much anything in it, for whatever you want to do.
Man... I just hope they keep a full offline installer before closing the shop. I'll keep using Winamp until I can't do it no more.
Cheers!