This program makes me feel all warm and fuzzy

As I've accumulated more and more data through my thesis project, I've become more and more concerned about the integrity of my backups. I keep copies of my data on a second hard drive in my main computer, on a raid-5 array on a remote server, and make backups of every thing to DVD's a few times a year. I rely on the fact that all those data are copied correctly, and so it's nice to have a utility which will verify that each copy is identical. This program has been quite useful in that respect:

http://www.md5summer.org

Although I've yet to experience a problem during these md5 checksum checks on copied data, it's still reassuring to have this little utility run through my data before and after backing up to make sure nothing has been reproduced inaccurately. It runs through 13.4 GB of data in around 20 minutes. If something is copied wrong, this program should catch it and report back with an error for the file that was copied wrong.