After reading this post on Jeff Atwood's blog, I decided to try one of the Raptor drives. I bought a 74GB drive to use as the primary on a machine that I wanted to repave.
I rebuilt the machine and was amazed at the difference it made. Boot time is noticeably faster and software installs went a lot faster than before. I expected some improvement, but didn't think it would be enough to justify the higher price of the Raptor drive. I was wrong - there's a big difference!
Based on what I've seen thus far, Jeff nailed it perfectly when he wrote:
It's gotten to the point now where I won't even consider building a machine without a Raptor as the boot drive. Sure, your computer may have 2 or even 4 gigabytes of memory, but going to disk is inevitable. And every time you go to disk, you'll become thoroughly spoiled by the speed of the Raptor.
Hmmm, maybe I should upgrade the 5400 RPM drive in my laptop to a 7200 RPM drive...