I'm not talking about SSDs, of course. I'm trying to find the fastest mobile hard drive in terms of responsiveness. I care less about how many MB/s on a sustained read the drive is capable of. I do want to improve my boot time and application loading times, as well as UI responsiveness. So . . . For these types of tasks, what is the fastest hard drive I can get? Anything from 250GB to 500GB would be good. I've heard positive things about the Scorpio Black 320GB, but also that it tends to vibrate excessively in the 13" uMBP (my computer), and that the Scorpio Blue 500GB is almost as fast. How do they compare in terms of the traits I'm looking for? Are there any other drives you'd recommend?