If you use iTunes on your computer, then the Apple TV makes a great addition since it will access & stream anything from your itunes to the system. The user interface for Netflix is great too. For $99, it's hard to beat and cheap for all you get IMO. I bought one for my dad for Christmas, and I hooked it up to my system just to try it out first. After 20 minutes I got online and bought another one to give him because I knew I'd never take the Apple TV out of my system.
-Brad