Apple TV can be awesome if they allow app developers to create apps for it. As it stands, the Netflix + Hulu Plus combo is nice but Roku has had that forever. Roku also has HBOGO, Amazon Instant Video, Dish World, a few news channels, live sports and more.
The nice integration between OSX, iOS and Apple TV is not enough reason to jump to Apple TV just yet but I'd switch in a heart beat if/when they add App Store to it.