Yahoo Music Engine
This post is a pretty good (if obviously biased) writeup on the Yahoo Music Engine. It's a cool idea, although I don't buy the line that they're just building a music player with "you" in mind and not with their own corporate interests in mind. I mean, Yahoo is a big corporate interest, isn't it? In the end if it doesn't make Yahoo money, it won't survive. Like Winamp.
iTunes has been serving me very well. AirTunes is awesome, and that alone would keep me using iTunes. My biggest beef with iTunes is that it's not open enough. There are things I want to do that their extensibility mechanism doesn't let me do.
The competition is good, though. It's cool that now we have 3 major companies battling it out to be the best music player. iTunes could use some updating, and Windows Media Player doesn't change often enough to really be much worry for them. But now that Yahoo is competing on the music side, and on the player side, perhaps Apple will get busy.
In the end, we'll all win.