When installing a new machine is an API call, we're all programmers now. -Limoncelli, on cloud computing, devops, and the importance of developer skills in system administration.
We're all programmers now. Programmers use source code control.
Things to put in your repository: Your scripts, programs, configuration files, documentation, and just about anything. If you aren't sure, the answer is "yes".
Keeping your configuration files in source code control starts out feeling like a luxury and ends up becoming a lifesaver.
Anything is better than nothing. Use what your developers use. No developers? Learn Git, Mercurial, or even Subversion. Desperate for a quick way to save configuration files history? http://www.nightcoder.com/code/xed (It is a wrapper that calls $EDITOR.)