I feel Togekiss would be pretty cool, to be honest!
It's rather cute, and I believe it could Fly as well; by having this Pokémon with me, I would be able to go almost anywhere, so long as it's willing to carry myself every once in a while, haha. Aside from that, it's also quite useful competitively, and if same methods were to apply in real life, I could imagine Togekiss to make things quite easy when it comes to battling and whatnot. Thanks to its Serene Grace ability, it would be able to take decent advantage of Air Slash, and with that combination, it could take down a handful of opposing Pokémon on its own.
Aside from Togekiss, Ninetales would be nice, too. It's got a beautiful appearance, and generally, it's very warm; when it's wintertime, instead of turning on the heater, I could snuggle with the Pokémon to warm myself up. Plus, this Pokémon has ability to summon sunlight at will, which I find to be kind of intriguing! If not Ninetales, Vulpix would be sweet, too; it's simply adorable.