I would choose the following Pokémon to follow me around:
The starter, most likely Chikorita. (Or all three, if I can trade!)
Flygon and Arcanine, my two favorite Pokémon.
My Smeargle Hidden Move users, simply so that they don't feel abused and kick me off a cliff when I ask them to preform Rock Climb...
And finally, the best of all. Shiny Pink Male Lopunny. How awesome would that be?
Of course, I'll alternate them, just so that everyone can stretch their legs.