There are better Mario Karts from a party game perspective, but Double Dash is the one I think of when I think of "the best Mario Kart." Part of it is, no doubt, childhood nostalgia peeking from behind the curtain. Still, I find the physics of this Mario Kart the most bombastic and fun to play. Additionally the fact that you get to choose your power-ups and that they're tied to character (and as such, a vehicle for characterization) is such a cool system; I'm a bit disappointed it never makes a return in some way.