The 5.1's are very nice speakers, and if you have the money, then go for them. If you get a 4.1 setup instead, I would go with the Logitech z-560's. The subv with the klipsch 5.1 has slightly better and louder base than the 560's, but the logitech sub sounds a fair bit better than the sub with the 4.1 klipsch setup, and it has more power. IMHO, you can't really go wrong using any of the 3 setups I mentioned, they just all have different price tags
Klipsch 5.1 $400
Klipsch 4.1 $300
Logitech 560 $199 (can find it for $140 w/shipping online)