whatever you do, don't buy an ibm (the "deathstar," as it is colloquiallly known among the cogniscenti). have purchased six since 9/21/01. since, two have failed. utterly, catastrophically, without warning or reason. and my experience is better than some. look around on the net.
used wds exclusively with success until 2 6.4 gigs failed. then switched to ibm because i was tired of the hassle. ugh.
recently installed a maxtor drive for a friend. was impressed, frankly, although i have no way to opine on its long term reliability. (i do notice though, that most of the maxtor sux posts on the net [and there are surprisingly few of them], appear to be either completely uninformed, or related to their software, or related to the problems that caused them to fall into disfavor with those in the know several years ago).
so, i dunno. guess if someone held a gun to my head right this moment and forced me to decide, i'd probably pick maxtor.
the 740 somethingorothers seem to have impressive performance stats, too, for what that's worht (reliability is my only concern).