I just graduated and did a similar thing. I wrapped up everything but my thesis before my senior year and spent those two semesters taking fun courses I didn't need like Intro to Nanotechnology and rigorous philosophy classes. The only regret I have is that I didn't take those classes earlier and thereby missed out on upper divisions in those departments.

That said, at my university your major only takes up 1/3rd of your overall credit hours so I had tons of time for electives and courses far outside CS.