Why is the fastest hard drive available in a PB only 5400 RPM? I know that isnt very slow, but it certainly isnt fast by any means. I mean you could get a fast external, but that defeats the laptop portability. Is it the technical limitations on the design of the PB or what? Do you think Apple may include it on the next revision? I want, but compared to some Apps on a PM with a fast drive, I find the lag sort of bad.