The Roku is by far the best-known Internet streaming box, probably followed by the Apple TV. But for those who want to be able to stream files from a USB hard drive or their local network, the Western Digital WD TV is probably a much better fit. At only $50 after mail-in rebate today, it's at the lowest price we've seen, and it's one of the cheapest streaming options available while also being arguably the most versatile and powerful.
The box gets great reviews, you can play basic games on it, and it'll play most files out there. Add that to the ability to stream from Netflix and Hulu Plus, and the WD TV outdoes most other options short of a dedicated home theater PC setup.