Unfortunately I can't seem to be able to come up with a solution to both the "Automatic nightly backups (no user intervention required after initial setup)" requirement and "Recovery from disasters such as a computer hard disk crash, natural disaster (hurricane) or a fire"...
As a photographer I find this problem to be a crucial one. My solution does not satisfy the requirements but works for my needs and does not take too much effort on the part of the user... I'm not familiar with fire-proof or hurricane-proof data storage and frankly I use so much space to store my images that unless a disaster-proof HD costs the same as a normal one, I'm not likely to buy one. I need a redundant 300 GB every two to three months.
So, here's what I got. Nightly downloadable information to a HD via network. The information is mirrored every other day to another HD manually switched out and stored in separate places (home and office would suffice or safety deposit box as suggested in an earlier post).
Using bit-by-bit data verification there isn't any need to look at the information.
The problem with software that automatically backs up files that have changed is of course viruses... If a virus changes the data and the data is then automatically copied to the backup HD you're in a jam... manually selecting files or folders to backup (at regular intervals) eliminates this problem but requires a little bit more work on the users end...
I'm pretty sure this isn't the solution but it works for me...

Yup, it is still on - the contest has been extended - see the original post above.

Is this still running? I can't find where to vote, or the other backup configurations to vote on.

Software: Actually I use a product that is developed for by company I work for, but it has not been released yet so I can not state any information here. I apologize for this. It's similar to Dantz Retrospect, but has more features and options.

600GB: It is an array, I use software to complete this... Windows Advanced Server. I have been meaning to change it over to hardware array for sometime. But as the saying goes, if it's not broken, don't fix it.

What backup software are you running on the fileserver? Is that 600gb a single drive or a raid array? what kind of raid card if so?

My backup solution is:

My home office has a complete backup solution for all of my connectible devices. I have an incoming cable modem which connects to my firewall. My firewall is connected to a gigabit network that runs throughout my house. On the network I have a file server with a total of 600GB of shared storage for my computers and devices. The file server does routine syncronization backups 3-4 times a day, meaning it will only backup changed files. The file server is also setup to backup my laptop/PDA when it's connected to the network. In addition, the file sever backup software will backup open or locked files, so everything is backed up even OS files that are always in use. Twice a day my file server is backed up to a hot swappable disk drive, every day I rotate out to a safety deposit box at my local bank (there are two more disks in here). This protects against hard drive failure, data corruption or loss, fire, or other nature disasters that are prone to my area. I pay nothing a month for the backup solution, the safety deposit box is free for me since I am a "preffered banker" of the branch.

Cheers!