HD Backup Workflow

Hello,

I'm trying to figure out a more permanent HD file backup system/work flow, and I'd like a better sense of what other people are doing. Right now my "system" of backing up projects is pretty hodgepodge; I work off of one drive, then back everything up to another drive, then eventually archive the project and burn it to DVD. I rarely get to the last step, however, and drives keep filling up. Until now we will just buy new drives, but this stopgap method doesn't seem sustainable.
Would people recommend a RAID array of some kind, or a server? Any brands you'd recommend? Any advice on a permanent solution would be much appreciated.

Thanks!
Grace