I imagine you need the USB to play videos and/or pictures? If you have a Windows Vista based PC with Windows Media Center that could be an option... if your computer is not close to the TV then you could look into a Windows Media Center Extender (start below $200). If you have an Xbox 360 on the TV you can also share your hard drives over the network and browse them through the Xbox Interface, and if you have a Windows based PC with Windows Media Center you can use the Xbox 360 as a Media Center Extender at no extra cost. For the price of $120.00 I'd much rather pay a little extra and buy a Media Center Extender so I could get the most out of my PC on my Television... or better yet buy a used Xbox 360 for about $30 bucks more and have a Media Center Extender and game system to boot.
http://www.xbox.com/en-us/support/systemuse/xbox360/digitalmedia/pc.htm
http://www.microsoft.com/windows/products/winfamily/mediacenter/features/extender.mspx
