CVS (Score 2, Insightful)

I have been using CVS to manage many different websites and/or projects on various servers. It doesn't store more then it needs (just the CVS folders) and it add, updates, patches and removes the files according to your repository.

Additionally you can use branches and sticky tags to keep track of files that don't need to be updated, or files that vary from client to client.

It is also easy to trigger and update over ssh or cron.

One downside compared to SVN is the lack of a binary diff mechanism, but I have been able to get by fine without it managing projects up to a GB in size.

Alex