I've had my G4 "Digital Audio" for a month now, and I was going to spend part of a bonus I just got (woohoo!) on a sound system for it. Question: what speaker systems can I buy other than the Apple Pro Speakers? I'm not an audiophile, so I'm somewhat at a loss at what to do with the "Pro" speaker plug. My iMac's sound system had a regular old stereo mini plug, which will only fit in the headphone jack of the G4. Any suggestions?