I'll second Jordan's Mom. Some toddlers don't like characters and if yours turns out to be a "screamer" it will be one of the worst meals of your life. Schedule it a few days into the trip.
My daughter (at 2 1/2) loved all the characters, but my son (at 3 1/2) was far more tentative. Fortunately, he was willing to see them - as long as they didn't get too close. We did all the "preperation" stuff, they'd seen movies, seen tape of the characters interacting with real people - so they had some idea of size - were familar with the characters - and he was still very wary.
That said, if your kid likes the characters, I don't think there is a bad one. If your child likes Pooh over Mickey, choose a Pooh meal. Two is generally little enough that the princesses aren't a huge deal yet. I'll put in my normal plug here for considering family style (Ohana's or Garden Grill) over buffet (Chef Mickey's) just because they are easier on Mom and Dad.