Everybody's been talking about the advent of iTunes for Windows, but what does Microsoft have to say? Nothing good, apparently, (Q&A: Choosing a Digital Music Service for Windows Users):
iTunes captured some early media interest with their store on the Mac, but I think the Windows platform will be a significant challenge for them. Unless Apple decides to make radical changes to their service model, a Windows-based version of iTunes will still remain a closed system, where iPod owners cannot access content from other services. Additionally, users of iTunes are limited to music from Apple's Music Store.
As I mentioned earlier, this [iTunes' closed system] is a drawback for Windows users, who expect choice in music services, choice in devices, and choice in music from a wide-variety of music services to burn to a CD or put on a portable device. Lastly, if you use Apple's music store along with iTunes, you don't have the ability of using the over 40 different Windows Media-compatible portable music devices.
I especially like the last sentence:
When I'm paying for music, I want to know that I have choices today and in the future.