I asked about adding an external HDD to a PS3 and found that pretty much any external drive will work, no limit on size. But it was reccomended that for greatest compatibility that it be formated using FAT32 and not NTFS file system. You can get a 500 gig external hard drive for $99 if you look hard enough, so I see no real reason to go through the hassle of upgrading the internal hard drive, considering how much it would cost to get a large sized notebook hard drive, and even then you are most likely still only getting a 5400 rpm hard drive... and even if you did get a 7200 rpm drive, you are most likely only going to create more heat inside the PS3.