Do look at the likes of Dali, Q acoustics, as mentioned by MaSh. If you can answer questions that what you think is missing from your current setup, it could be easier to pinpoint where the weaknesses are. Some forum members have benefited by upgrading the subwoofer on Yamaha home theater package, others have benefited by upgrading the center channel. Also if you can mention the room size,and how far apart the left/right speakers are it would be great.