I think the biggest knock against iTunes, greater than the fact that it's a buggy piece of shit on Windows (and I've even seen Mac users complain about it), is the fact that it cannot edit metadata. It's perfectly happy to let you try, but it only updates a proprietary database that is shared with iOS devices and nothing else. iTunes wants your music to be presented beautifully on iOS products, which is great if you're in the whole Mac cult and you don't buy any non-Apple stuff, but no metadata in other media players and on non-iOS devices is just artificially making the Apple stuff better. Which is actually most of Apple's business model. Steal, undercut, make 'em love ya for it. If iTunes could actually edit metadata in the file itself, it would be just another library-based media player, but it isn't even that.
Winamp 3.x was crap. Always was.
There never was a Winamp 4.x series. The official explanation was that 2+3=5 so the next version would be 5.x. Winamp 5 made a lot of folks happy by letting you make it look like Winamp 2.
LOL at the AOL shills suggesting everyone use the new Winamp but offering no solution for the setup loop bug. Put up or shut up.
Also, I'm almost surprised it hasn't been said. Winamp 2.x was never able to properly handle VBR (variable bit rate) MP3s. Some it handled fine. It played nearly all of them impeccably, and that's okay. The base functionality was there. Sometimes the total time display was off or would fluctuate. They may have fixed that in 5.x or even 3.x. It never bothered me too much, but I found it annoying that Winamp couldn't lock down the total running time of a song until you played it all the way through. I mean, really?