If it wasn't for cPro (
http://cpro.skinconsortium.com/) adding better functionality into winamp such an inline playlist search!, chapter a-b repeat lists!, and just giving skinners an easier way to make decent skins (at least some) then I think I would have jumped ship years back.
Though it would have been hard seeing as there is just less flaws in winamps design compared to other players. And it still has a lot of really good plugins that just add to its already great base functionality.
Also prefere the single user interface with the awesome media library with smart views built in.
The only thing missing from winamp was a proper tabbed playlist interface like aimp3 with the options to control it for when adding songs from medialibrary or external opening mp3. It's a shame aimp3 has that stupid old style winamp2 design of seperated interfaces before it was possible unify the components into a proper seamless SUI, while its media library is the ultra suck it doesn't even look like it fits in.
foobar is just a joke, still its lightweight which is code for bare minimum crap to me, its like it never left beta, and things winamp provides out of the box you need to spend a lot of time setting up like columns ui.. sure you can get something reasonable in the end for one specific type of gui setup (actually skinning it is a nightmare), and its media library is crap and very much a player centered around just playlists and album art really no comparison to everything winamp brings to the table along along with its +plugins+cpro+skins etc
I'll be keeping my winamp setup for as long as I'm still using windows, hopefully if its open sourced it can finally get a new life fork instead of being left in stagnation like it has for so long under AOL.