Probably Alakazam due to it's high intelligence and psychic powers that I assume could be used in healing of a person. If not Alakazam, then Blissey who would have experience in nursing that would be really helpful.
I would most likely have Uxie. It is said to be the most intellectual of all Pokémon, so every time I got myself into any sorts of trouble, it would always be able to figure out a way to help me get out of it. Uxie also has access to a variety of moves that'd be able to aid me throughout my life, such as Protect, Heal Bell, and Future Sight. Future Sight would enable this Pokémon to detect what lies ahead of me in the future, so that I can always be prepared for just about anything. With Heal Bell, this Pokémon could keep me healthy at all times—mentally and physically. Protect would allow Uxie to keep me away from being hurt, and stop me from getting into any kind of a major accident. These moves may not be very useful when it comes to battling (well, unless you use them strategically, of course), but they can certainly be of great assistance in daily life. d:
I'd also like to have a Vulpix, if possible! It may not be as helpful as Uxie, but every time I got to see it, it would always be able to brighten up my mood. :) Vulpix are extremely cute and cuddly, and they're very easy to befriend!
Blissey; she could teach me how to better heal, and take care of myself, as well as people close to me.
Machamp; it could train me physically, try to be buff like it... LOL
Clefable; if things are going rough, but I had Clefable at my side, I'd always have that friend to reassure me that life is great, I should be happy, etc. Perhaps it could teach me a real-life equivalent of Metronome? :3
I'm sure her and I would get along great. Something nice and cool to chill down the summer days in the middle of the desert (Southern California). I think it'd help me a bit by looking at something less fortunate than I I suppose. Besides, she's a ghost. She can float through walls and chill my soda for me! Great, koffi~
Genesect...cause why not?
It could do all sorts of stuff for me...using its Drives! Like heating my coffee/tea, instantly freezing my ice-cream and bring me back electricity when it turns off, so I can have internet! Like so many possibilities!