The IBM's are very fast (the fastest I've seen), and extremly quite (you will not hear it)
Seagates are supposed to rock speed wise but if you need the storage you'll need more then a 40GB.
Out of that list I'd probably go for the IBM just cause I've used them and love them. A LOT of people have had the fail on them. A chip overheats and ruins the drive. So if you do get it keep it cool!