Thanks for pointing out the power of open formats. Once you do the initial install purchases pop right into itunes. I take it to the next level and use LockerSync from MP3tunes.com. This nifty software sits i the background and anytime a new song touches your computer it instantly adds it to your personal locker online so you have a permanent backup. This gives you the safety of never losing your purchases but also lets you stream the music from any browser and have it instantly synced to any computer connected to your personal locker. So you can buy music at work and have it waiting for you automatically on your home computer and laptop. It's a great example of the power of what you can do with MP3 files.
My Experience With Amazon's MP3 Download Service