don't wanna waste words boring anyone with background, so here goes -- i want an external hard drive, 40 to 60 gigs small is fine. bigger okay, but not at the expense of too much money. usb okay, but prefer firewire. must work seamlessly with my iMac g5. it will be for back up primarily, and am considering a raid solution. apple store is too expensive, and i keep hearing that externals are so price-competitive now. may i please have recommendations. thank you.