I felt vaguely ill as I hit the buy button for a OWC Mercury 300GB.. mostly because I haven't spent at least a week researching external hard drives. I almost bought a seagate barracuda and an enclosure but I figured it was about the same price with more of a hassle -- and the 5 year seagate warranty is rather strict concerning external hard drives. Macworld.com rated the OWC Mercury highly and a search of this forum seems to give it a favorable rating.. Now I have a better chance of buying a iMac from a private seller here instead of the apple store, at least. I originally wanted to upgrade the hard drive in the iMac to 500GB and the iMacs from private sellers rarely have upgrades. Now I just have to decide between a 17" and a 20" iMac.