I've got a MBP 2.2GHz Core 2 Duo that I bought new in October, 2007. It came with a 120GB hard drive, which is no longer big enough. I want to put in either a 320GB or a 500GB drive. The former will probably be bigger than adequate, but if the larger one isn't that much more expensive, I'll probably go with that one. My priorities: Quiet Reliability Performance (I'm NOT doing a lot of video editing) Bang for the Buck Heat - especially if running hot means that the fan will be screaming and therefore, noisy Even though performance is third on the list, it still matters. So I'm thinking 7200RPM, but it seems that lots of people have equivalent performance with the WD Scorpio Blue 5400 RPM drives. I see various threads here that address one drive vs. another, but nothing recently that more covers the gamut. Does the 16MB vs. 8MB cache size make a real world difference? Anyone have enough experience to offer an opinion based on my criteria?