Western Digital makes a very good HD. I've had a few last me 10+ years. SeaGate, Im not too fond of, I've had them break down rather quickly. Maxtor are good drives, not as good as Western Digital in my opinion though.
Above all, I wouldn't put my faith in any one HD though. if it's important, back it up, often. You can link 1 or 2 slave drives in your Computer and setup Sync folders in them to sync all your work. Keep the computer on overnight and set the transfer up for say... 9PM. gives it almost 11 hours to snyc information. It doesn't rewrite everything, just anything with a last accessed date on it or that wasn't in the designated foldfer before. At first, it seems like a pain in the *** to set this up, but I assure you, once it's setup it's worth Syncing folders.
Also, you can buy a HD Toaster. Makes internal drives into big memory sticks. I have 12 80g HDs laying around I throw random stuff on. Pictures movies knick knacks. Doesn't require a restart to boot the drive up either which is nice.