I want to cram a 500GB drive into my 20" iMac G5 2.1Ghz/iSight. The contenders are Seagate Barracuda, Hitachi Desktar, Western Digital Caviar, or Samsung SpinPoint. I've had good and bad experiences with all those brands, but I'm leaning towards the Seagate or WD. Anyway, the real issue I'm concerned about is the thickness of the drives. My PowerBooks require hard drives that aren't thicker than 8mm (or whatever the exact dimension is). Does anyone know if this is the case with the iMacs?