Buy.com has the Pioneer 600W HTS-GS1 5.1 Surround Sound Speaker System on sale for $99. It’s targeted towards 360 owners, but this seems like a solid system for anyone. It has most of the connections built into the sub, which saves space. The display appears to be designed to match the look of the 360. And the remote has 360 specific buttons on it. This thing has really good reviews on Buy.com and Amazon.

Link: Pioneer 600W HTS-GS1 5.1 Surround Sound Speaker System