I purchased a MBP 15" last July to use at my job. My employer has finally decided to upgrade my 3-year-old (windows) laptop (which I wasn't even using), with the exact same configuration MBP I bought for myself: the high-end 15" MBP w/ 7200rpm option. My parents will be buying my current MBP from me. I would simply sell them the one I got from my company, but the company probably cares about the serial #s matching what they gave me. So, is it safe to simply swap the harddrives? It seems like that would be much faster than doing a time machine backup & restore. Is there anything in the OS that cares about the hardware's "hash" or "signature", like there is in windows XP? I know my MAC addresses will change, etc., but what other problems should I look for? Thanks in advance.