|XP is just a number|
This is going to be another piece you will think is unnecessary in the beginning. Years ago, I saw version control described as a time machine for your development.
A version control system allows you to go back to earlier versions of your code or compare your two different version of code. This is most useful while things are changing.
For example, imagine that you've got a mostly stable version of your code in place. Now imagine you have a great idea that will only take a few minutes to code up.... 4 hours later, nothing is working and you are wishing you could go back to where you were 4 hours ago. Version control to the rescue.
You could do the same thing by zipping up your entire site any time you feel it is worth keeping.
Version control can also help with seeing what changes you have made (to help you find where you went wrong). Say you want to compare what you did 2 hours ago with what you have now.
The point of enlightenment for me was when I realized that I could use version control proactively. Make sure everything is under version control. Try something experimental that might break everything. If it works, keep it. If it doesn't, toss it. No real loss.
Of course, there are better and more advanced ways to make use of version control, but these would be helpful right away.