I upgraded to a dual SSD/HDD several months ago, so I have a 256MB m4 Crucial SSD and my previous HDD, 500GB Momentus XT. Now, I find myself running out of space on the 500GB (SSD doesn't have much left either). I usually use it to store videos, pictures and music. I have been looking around and I can't seem to decide which would be best. It seems like to get a 7200RPM drive, the max is 750GB and to get a 1TB, max is 5400RPM. Cost between the two is negligible, and of course bigger would be better. My concern is that if I get the 5400RPM drive, would there be any performance changes on my MBP? The Momentus XT is a hybrid, so it's quite smooth. I would want something similar. Is there really a noticeable difference between 5400RPM and 7200RPM? The drives I'm looking at are the WD Scorpio Blue (1TB) and the Scorpio Black (750GB).