As the owner of the Z-5500s:
- They're awesome for games and movies. The sub is just about the only proper SUBwoofer I've ever seen in an HTIB. Then again, it's freaking HUGE
- They're not so awesome for music. Most of it sounds nice, but stuff with a treble-aggressive sound will sound harsh then played loud. They can get pretty loud before that happens, but in a small room you should be ok.
- The default bass config is WAY too high. Mine's at 10-15%-ish. Also keep the front speakers pointed out straight instead of pointing to you. This helps ease the "harshness".
- The included remote and control pod are very neat/intuitive/easy to use. DTS and Dolby decoding is a MAJOR plus if your soundcard has Dolby Digital Live or DTS-Connect.
As nice as a proper HTPC setup would be (which I would heartily recommend in a bigger room with a big TV, etc), I thing an HTIB like the Z-5500 will be a much better investment for your specific case.