well.....
a home theater system will have the potential to sound a bit nicer.......
but unless you're going to use it strictly for music and movies, i'd get dedicated computer speakers.
the reason i say that is that computer speakers are set up a bit better for taking the abuse of low-quality system sounds/internet music, etc. Where there's a definite possibility of tearing up home theater speakers that are really only made to play back high quality cd's and dvd audio.
I had a yamaha home theater system hooked up to my computer for a while, and ended up selling it and getting a logitech 5500 instead, because the home theater speakers tended to make the lower quality system/internet sounds, etc. sound very bad, and the speakers would tend to distort and sound very raw. The logitechs don't sound QUITE as nice when watching movies, but they handle the less refined low-quality sounds much better, giving a better all around setup for workstation useage.