I am using Mercurial[/url] for my small (single-dev) projects.

I like it because it is distributed, simple and scalable. And most important: You don't need a server if using it one a single machine. The repository is stored in a sub-directory of your project.

Side-effect: The file-backup of your project-folder will also back up the whole version history.

With Mercurial there is no excuse left for living without VC! 😛