Heh, the other hifi speaker is away on the other side of the desk. That 'bag of balls speaker' is just to provide a convenient location to plug my headphones into, and for the odd occasion that I actually can't use my headphones (i.e. if I'm listening out for the phone or something).
I tried opening a set in Ableton Live (recording program) that my previous PC took literally over 5 minutes (I timed it) to load, and then played at about a quarter speed - this new PC loads it in circa 30 seconds, and plays it at full speed. I've yet to test any crazy synth patches or modulation effects (one in particular crashed my old PC every single time I touched the mod wheel), though I have noticed that the piano and drums plugins load up mega-fast too.
I've only tried throwing HL2 at it so far (plot refresher before I buy the Orange Box), but temps didn't go above 36 degrees in either HL2 or the few quick blasts of Prime 95 I gave it, and they dropped like stones back down to their idle temps in the mid/upper twenties. Lots of lovely overclocking headroom, methinks. Though after the trouble I had getting this thing together, maybe I'd best keep it at stock before I try any overclocking hijinks.