Agreed. Not only that - there's honestly nothing like Duke (old or new) on the market right now. We have a glut of hyper-realistic shooters (CoD, MoH, Halo, Killzone, etc) and just not enough silliness.
That alone is enough to make Duke stand out from the rest I think. I mean, how many games start off with you taking a piss in a urinal, using the right thumbstick to control your aim?