Isn't all of those 9.5 mm now, not like earlier when some models was 12.5 mm, thus no longer making this an issue?
Edit: Had to change a faulty Hitachi Travelstar once, but it was replaced without any hassle (and I didn't loose any data as it worked all the time, just not well ), but my other Travelstars have worked excellently.
But I would like to replace my iBooks 60 GB Fujitsu with a 120 GB Seagate Momentus 5400 disk when I can afford it. The extra space and the thought of a Seagate is really tempting. If the Momentus is just half as good as the Barracudas 3.5" desktop drives, which Seagate also makes, they should be awesome.