Years ago, during my study Computer Science I developed in Java. The last of my Java years I made use of IntelliJ IDEA as my Java environment. IntelliJ IDEA is a very intelligent IDE from the same guys as ReSharper. I wasn't using a source-control system but made use of a very nice feature: Local History.
I just found out a CodePlex project: Visual Local History 2005. Visual Local History is a Visual Studio 2005 and 2008 add-in that will provide some kind of Local History. It can integrate with some predefined comparison tools. Sadly it is still in Beta, but will that prevent us from using it? At least it is released in GPL.
I'm not advocating using Local History as a replacement for source-control, but sometimes the changes you made are very large and it takes some time before you are able to check your into your source-control. I think Local History can work without any trouble side-by-side with your source-control. This way you won't loose any control by not using a source-control. You're even gaining control by the ability to browse through your local changes.
This all sounds very nice. This kind of local history could be nice for using with all kinds of documents.