Yes... computer speakers are a joke really... but I recommend either Altec Lansing or Creative ones if you really decide to get 'em... they have pretty good sound quality... Creative's sub's tend to be better than Altec's(deeper and richer sound), but the Altec's satellites' tend to be better in terms of sound quality.. I have both a set from each company, both 4.1's and they're great. I use the creative on my gaming system, and altec's when listening to music on my other..
Seriously.. I don't see too much point in 5.1, one extra speaker, unless you're playing some serious FPS game or watching some crazy movie.. you won't notice much difference... just waste of space... if it was home theatre, that'd make more sense... but geez its only a computer..