A couple things to think about.
First, if you buy a normal VelociRaptor and remove the IcePak heatsink, you void the 5 year warranty. What you want is to buy one that is not manufactured with the heatsink, thus retaining the warranty. That model is
WD3000BLFS. It is considered an enterprise level drive and thus availability is limited and price is high.
Second, even though they are 2.5" in size, they are thicker than normal notebook drives, thus would not fit in most situations that call for a normal notebook drive.
Third, if you want snappier performance, a good SSD runs circles around a VelociRaptor.