How "much" do you keep under version control?

[eluser]mtbkrdave[/eluser]
Hi Y'all - CI newbie here, making his first post...

I've been poking around with CI under LAMPP for a few days, and I'm ready to start building a practice app. I'd like to keep it under version control, mostly as a best-practice but also because subversion has saved my butt on many an embedded C project, so I'm a big fan.

My question is: Just how "much" of the structure should I keep under version control? The entire CodeIgniter directory, including the framework files as well as my own? Or just the directories containing my project files?

Thanks,
[medic]dave