I don't building a computer based home theater surround system is a bad idea. I don't know your budget and I am not sure if you are looking to watch movies more than music so I will give you middle of the road advice. Russound builds a quality amp which has the sub out line. Nuforce has a better form factor that is small but powerful for its size however the amp is pushing 22w into 8 ohms doesn't sound like much but you would be surprised if you have efficient speakers, meaning speakers that don't take much to drive them. Nuforce offers unparalled flexibility. Audioengine can get it done from head to toe, check them out. I have some of their products and it is outstanding. Instead of a sound card take a look at Audioeninge's D1 dac and N22 amp then consider hooking them up to either Energy sattelite speakers or Audioengine's A2. If you have enough change bite the bullet and get an HSU amp, the lowest one on the latter is $379 USD, consider Velodyne and Audioengine's S8 seties sub. This will get it done the right way. If you like movies consider a bigger set of speakers, in the Polk Audio family of speakers or Audioengine's self powered A5 speakers they are plug and play giving the end user needed options. If you don't get a subwoofer for the moment Emotiva and Onkyo amps are worth considering and reasonably priced. If you can swing an NAD integrated amp I think you will really enjoy the performance. Don't overlook speaker stands. This set up will have plenty of power for movies that driive big sound. Take your time, think it through and most of all, enjoy. Best.