I'm surprised Moreno isn't in here tearing this thread up with all his straight talk about how Double Dash is the best. I was just going to quote him with "this!"... seems like I actually have to explain myself, though. :/
MK:DD has the best controls, the best items, the best tracks (no matter the small-ish selection), some of the best karts, the best local multi-player, and the best mechanics.
It's just the best. (Does 'best' still sound like a word to you?)