Mango

Heart Gold and Soul Silver are wonderful names and are better than any name used in a hack. Dusk Gold? Dawn Silver? Ridiculous.

Giratina has too many legs, Palkia is strange and I wouldn't use either one in a battle. So it simply has to be Dialga.

*sigh*

It's not a heartrending decision like choosing between Latias and Latios.

i just want to have the event arceus follow me around at all times i think that it would be cool

That makes me wonder. What will Arceus' mood be when you talk to it?

"It looks like Arceus wants to make another Bidoof!"

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.