Just pulled the trigger on a 2.4 unibody macbook with 4gb of RAM to replace a G5 iMac with a blown power supply. I had assumed that the HDD was a apple only install, but the store clerk assured me otherwise stating he had installed a 7200 drive himself. The one thing I'm not really sure on is what the difference between SATA, SATA II, SATA III and SATA 300 are. More specifically I'm not sure how these will affect compatibility with the new macbook? Lastly, is it ok to slap in the new drive clean and reinstall with the OSX installation CDs, or would I have to clone the drive? Thanks.