I think I would give it to Saints Row, particularly SR 3.
I love that game and had completely forgotten about it. I loved grabbing a tank and heading around town, getting the highest level "wanted" category (or whatever that game called it) and watching all the mayhem.
I'll never forget the intro to SR4, either. Was playing with my son who was a lot younger then, and we're watching the cutscene play out with the president and the aliens. It's pure madness. And the president leaps on a rocket that is blasting off, holding onto the side of it, and everything was just so crazy over-the-top, my son suddenly said, 'merica! and cracked me up.