Re: What computer speakers are you using and why?
Klipsch ProMedias pretty much suck because they have so much boom from their subs. You pretty much have to turn the bass off for them to sound natural, and even then the treble is pretty grating. I bought a set and relegated them to my gaming PC for my (more forgiving, shall we say) girlfriend. For much better sound, I recommend the Cambridge Soundworks' MicroWorks II 2.1 set ($249). They used to have two smaller systems, the PCWorks ($79) and the SoundWorks ($149), but apparently both are discontinued and unavailable direct. All three of these Cambridge 2.1 systems were originally designed by Henry Kloss.
The MicroWorks speakers are small and don't emphasize mids or high frequencies like lesser PC speakers do; the sub is not boomy but naturally integrates into the satellites' sound output. I play the MicroWorks from my Mac Pro all day long, listening to my large iTunes library and watching occasional videos and DVDs. If you can, try and go to one of their stores and demo them; if not Cambridge has a very generous return policy.
"I have always wished that my computer would be as easy to use as my telephone.
My wish has come true. I no longer know how to use my telephone."
— Bjarne Stroustrup (creator of C++)