Also, it's worth mentioning that you will not be able to fully utilize the speed of the 7200rpm 16mb hard drive when you're connected with USB. Get an eSATA enclosure if you have the eSATA port, or look into cheaper 5400rpm drives. If you get a 5400rpm drive, you can get up to 500GB instead of 320GB. Only worry about 7200rpm if you have eSATA or are switching it as an internal drive occasionally.