Posting this in the macbook pro section deliberately because the unibody 13 inch macbook is essentially a 13"MBP I have about 10GB free in my standard 5400rpm 160GB harddrive and am now thinking of moving to a 7200rpm 320GB one. Few questions: 1. How much of an impact will this have on performance? Would this make a significant one? 2. Can anyone suggest any known 'good'/reliable 7200rpm drives? 3. How much of an impact will this have on the battery life? I get good 4 hours currently on it and really like that I dont need to carry the powercord into school for the odd lectures. And I intend to clean install snow leopard on the new drive. Will need any formatting of sorts or is it just connect and install from drive? I then plan on using the 160GB as a backup one.