I'm entering graduate school this fall, and am trying to choose between the top-of-the-line iMac G5 and a mid/lower level PowerMac G5. Price-wise, there's no contest (since I'd need to buy a display for the PM also) and space-wise the imac is great, but how much am I giving up in performance if I get the iMac (G5 2.0ghz) instead of a dual 2.0ghz powermac? I really just use my mac for word processing, net access, burning dvd's, mp3's, watching movies, etc. No video editing or anything. My current setup, a PowerBook G4 867, is nice but can get a little sluggish sometimes. I want to make sure my next computer can run OS X blazingly fast. Thanks.