Seagate makes a great product, and their prices are now competitive with WD. At similar price points, I choose the Seagate also.
Bart's suggestion about NAS (Network Attached Storage) is worth considering for the low-end or ultra cheap guy like myself. It's my impression that there are some good choices around the $1,000 mark, in addition to the great choices for tens of thousands of dollars.
But there are also some interesting options for around $300-$400. WD and Maxtor, I think, have firewire/USB drives that also have t100 ethernet ports. This means they can sit on a network cable like a network printer or a PC does, and all network members could have full access to it. T100 is not a fast protocol, t1000 (gigabit) ethernet is roughly the speed of firewire, so t100 is one tenth of that. But for backup, it's an elegant solution.
For the grand that he's talking about, you're getting fast access and it APPEARS, you have the ability to swap out drives. This is important, because when you have 4 drives in a RAID you have 4X the breakdown likelihood. If you can't remove the drives, which is the case in the fully enclosed systems (LaCie), the entire product is shot.
For pure pathetic comedy, you can build your own NAS. Any old computer will do, or even just a cheap board and chip. You just start hooking up hard drives via $40 raid cards. This system looks terrible, works OK, and the TCO is around $200 plus the cost of drives.