Is the 10,000RPM spindle speed of Western Digital's VelociRaptor line of high-performance SATA drives a marketing gimmick??? I think so, but I also want to know what you think about it.
My thinking is regarding how VelociRaptors get their low access time. It's not the higher spindle speed that provides most of their advantage (in fact, the spindle speed only makes a difference of 1.17ms on average, between 10,000RPM and 7200RPM - not even half the overall difference between a VelociRaptor and a fast 3.5" drive) - it's the faster movement of the head assembly.
Hypothetically, an otherwise-VelociRaptor-like 7200RPM drive would draw less power (and the VelociRaptors are already light on power), run quieter (at idle, anyway), spin up faster (or in the same time, but drawing less current), and cost less. At the very least, it should perform closer to the VelociRaptor than to a standard 3.5" drive.
Think about it: If you can make a 10,000RPM 2.5" drive that draws less power than any 7200RPM 3.5" drive, imagine how power-efficient a 7200RPM 2.5" drive would be.