i was on my friends iMac today, he has the same exact one as me, imac 24, 2.8, 2 gig ram, but heres the thing i have a Barracuda 7200.10 SATA 3.0Gb/s 500-GB Hard Drive, and he has a WD Caviar® SE16 HD, two different kinds of HD's same imac, he didnt change his HD, neither did i, both ordered from apple, never opened. which HD is better? is there a definate better one? his computer is quieter than mine, my fans are whirling faster cuz my desk is enclosed, his is open. is one of them more reliable than the other? faster? also, the CD drive is different, he has a OPTIARC DVD RW AD-5630A, and i have a MATSHITA DVD-R UJ-85J, is one of them better than the other?? thanx alot, im just very curious!!!