I have set Quicken to back up to a file that I call "bup 2006-03-19". Every week I change that, so I will have weekly backups since, well you get my drift. This is on the main drive in this computer.
In addition I use Karen's Replicator to back up the working file(s) (using a wildcard that encompasses all files) to a different drive. I used to use a network attached drive (Buffalo Link Station). However, when that one blew (again), I decided to take my losses, and used a hammer on the disks in the hard drive, then discarded everything. I will not buy anything Buffalo again (YMMV).
Replicator can be found here as freeware, although I supported karen by buying her CD with more software.
I think it works similar to xcopy in collaboration with scheduler, but I'm not too swift and all those switches are too complicated for me. Anyway, Karen backs up my files at 2 AM to another drive, and I just have to go and clean up by deleting files and folders every month or so. Luckily I have seldom had need to resurrect a backup, althoug the few times I did, things worked like a charm.
Just a reminder, Karen will not backup files that are in use, so the "Fail" messages she sends are most likely that, files in use, like log files in Eudora.