I'm really sorry but if you actually have to argue for [the formalization of] source control in a development environment, you're in a hopeless situation. If your boss actually needs to be convinced that source control is a worthwhile endeavor, your boss is simply not suitable to be a manager of a group of software developers. In order for someone to effectively manage, they really need at the very least a basic understanding of the landscape. I can't even imagine what's going to happen when you actually need to argue for something that's worth having an argument and doing a presentation over.
Developing without source control is like driving a car without breaks. You lose the ability to do seamless concurrent development, you lose your code getting backed up in working copies, you lose the ability to do historic research via code annotations, you lose the benefit of seeing the context and comments that accompany discrete changes, you just lose, period. Using source control is so obvious and has so many benefits, it's shocking that you'd have to justify it.
At work, we use subversion, but some developers (myself included) use Git locally via the git-svn bridge. For personal work, I use Git.
