Q Acoustics 1010i 5.1 speakers
Yamaha RX-V667 receiver
The computer itself isn't anything special but it's still able to run Crysis smoothly with max settings at 1920x1080 and 4xAA.
Intel Core i5-750 @ 3.8GHz processor
ATI 5850 graphics card
4GB Corsair XMS3 RAM
1TB Samsung Spinpoint hard disk
Here's an old photo showing the rear speakers aswell. The sub woofer I'm using is a Q Acoustics 1000Si.
The 1000Ci center speaker that you can see in this old picture has now been replaced with a regular 1010i speaker to match the other four. The reason I swapped it was because the 1000Ci is designed to give clear dialogue in movies but I wanted to use five identical 1010i speakers because it gives better integration which seems to work better for the sound effects you get in games.