I am a recent (as of yesterday) college grad - BS in Computer Science. I've been a huge fan of version control ever since I got mad at an assignment I was working on and just started from scratch, wiping out a few hours worth of actually good work. Whoops!
Since then, I've used Bazaar and Git (and SVN when I had to for a Software Engineering class), though mostly Git to do version control on all of my projects. Usually I'm pretty faithful about how often I commit, but on occasion I'll go for a while (several functions, etc.) before writing a new commit.
So my question for you is, how often should you make commits? I'm sure there's no hard and fast rule, but what guideline do you (try to) follow?