Title says it all, mainly concerned as I have a friend who does well with a 640GB hard drive in his custom built PC. I would like this in a notebook, as I have backup media and important work worth about 320GB (external hard drive I'm looking into selling because I do not like its performance on Windows, for that matter), and I'm looking to use half of the only hard drive I'd have in a MacBook for it. So, I would have the other 320GB for miscellaneous things. Predictions, suggestions, ideas? Will prices be pretty reasonable? Thanks everyone.