320GB Western Digital 7200rpm should do. What sucks is that i had my Mac backup drive temporarily formatted to make the change for my new PS3 internal HDD which i'll get within a week... and i just installed OS X Lion on my Mac. IT CRASHED, locked disc, corrupt startup disc, clean re-install lost all my stuff since i wasn't running Time Machine with my back up hooked up to my PS3 etc. Lion is glitchy as of now, beautiful OS, but needs to be made a lot more stable.