The 6500 came with a 2 or 3 GB ATA hard drive, so you can replace your drive with any IDE drive on the market... I've used Western Digital, Quantum and Maxtor drives, and all are recognized by Apple's Drive Setup utility. These drives can be found pretty cheap, generally at or below $10 per GB. My guess is your computer will only be able to accept one drive (i.e. there is only one IDE connector on the controller card), so it might be wise to back up your current drive on removable media before making the switch. Your other option is to get an external SCSI drive and connect it to the external SCSI port, or an internal SCSI drive and an external SCSI case... but the best option is a new IDE drive.