Look me up if you guys are playing in flying spaghetti monster ...

IGN : FurankuriN

There really isn't a "best" ad carry. Depending on the play style, like for pressure of pokes, go ezreal.
If you are looking at late game, usually Kog Maw / Vayne would be the better choice.

Graves is pretty good for pokes as well. Corki is a poke-er once he gets his lvl 6.

Caitlyn can utilize her long range, but it will be tough against a poke ad carry and if he is good at skillshots.
Ashe is pretty decent for poke with her second skill, and with her ulti and all.

Well, it still boils down to what style you / your team is playing, be it pressure game or late game.

Good luck training your ad carries For an effective ad carry, make sure you train your last hits and I mean for farming.