Most (all should) developers use some sort of source control app to maintain a history of their source code. In using it, you may find that you'd like to have something similar for personal stuff. I know I do... there are tons of things I'd like to store:
I've mostly used Microsoft's Visual Source Safe, but I've never been happy with it. It always feels like it's held together with bubble gum and I cross my fingers it never gets blown up. I also don't like things that use the file system as their storage mech... especially when it's version control. Eric Sink started a company (SourceGear) a while back and has a nice source control application called Vault (latest version v2.0.3). It's very nice, and does cost a few bucks, but, it's free for single users... PERFECT for individual use. It's built 100% with .NET, IIS and SQL 2000. All data is stored in a MS SQL 2000 database (or MSDE for those who want the limited free version).
Personally, I give it two thumbs up for personal data storage. Also, it's GREAT when you have a work laptop and a personal network at home... just backup and restore the database between the two environments!