I'm alright with either title winning, but I like Mario Kart 64 more so it has my vote. Both games were amazing and always fun to replay. Twilight Princess was a breath of fresh air after Toon Link upset a lot of oldschool Zelda fans and it also had a lot of other great things about it such as the wolf form and a soundtrack full of beautiful remixes of old tracks and several new gems. Midna was rather annoying though, the game loses some points due to her.
Then there's Mario Kart 64. It took the Mario Kart series and turned it from a novelty into a megaseries. Everything that was wrong about the first one was fixed in 64. Gone were the annoying predetermined order of intelligence in the computer players. For example if you chose Bowser then the computer order was ALWAYS Mario, Luigi, Peach, Yoshi, DK, Toad, Koopa, or something like that. No matter what, every time you played as Bowser. Each character had an annoying predetermined order such as this. Then there were the character exclusive items that the computer got but you didn't (Toad's mushrooms, Mario's stars, Bowser's fire, etc) and not enough track variety. Mario Kart 64 fixed ALL of these issues while also giving us Wario and the chance to play 4 people at once. It was so epic for its time and has stood the test of time. As much as I like Twilight Princess, Mario Kart 64 is the more enjoyable game of the two so I voted for it.