I am a photographer who is working exclusively from a MacBook and I need to buy some external hard drives. I am thinking a Mirror RAID (2x500 GB) fir the images, and an 80 GB for the main disk. Any suggestions? I would like at least 7200 rmp, and Firewire is a must. It would be super-cool if the 80 GB could back up automatically. Thank you for your help.