You already pay every month for streaming video from Netflix, Amazon or Hulu Plus, but these services are a lot less fun when you can only watch them on your computer or mobile device. Starting at just $49.99, the Roku box lets you play content from any of more than 700 online video channels on your TV, without the hassle of connecting your laptop or tablet to your home theater. With Roku, you can even play audio-streaming services like Pandora or engage in a game of "Angry Birds," right on the big screen. The $79.99 version supports crisper 1080p video.