logitec actually has surprisingly good surround sound systems. and for a bedroom/small rooms, i find it better to invest in a PC surround sound system, instead of a cheap theatre in a box system.
this is their top tier surround sound system, ranked #2 on head-fi, has very good reviews, and just a little over your price range. but you can easily find a cheaper price with a little bit of googling
trust. this thing is a beast. when you see that the sub woofer has an actual warning to keep it 2 feet away from electronics because of its magnet, you know you got a powerful sub.
the reviews on it are nothing but spectacular.