They are all great brands, but avoid IBM and now they are called Hitachi
for the seagate barracudas there is a jumper on the back which you have to remove for it to work at 3gb/sec otherwise it works at 1.5gb/sec just a little heads up as it may be the same on the wd harddive
Thanks i'll keep that in mind wow i never knew that IBM is now Hitachi, couple months ago i realized that Seagate owns Maxtor as well so i dont even bother buying a Maxtor