1. Double Dash because you can choose two characters in one kart. I thought that was a fabulous idea. Some of the Karts and Tracks were cool. The game was a little too easy, though. I beat the game in two days. lol. Still loved it nonetheless.
2. Super Mario Kart because I liked the character themes. The music was pretty awesome and the tracks are really cool. I like the game because it had the challenge that the others didn't: Try to win first place without any Drift Boost. I enjoy the game, I play it from time to time for the fun of it.
64 and Wii were alright.. I guess.
For DS and GBA, I never played, so I don't know.