I'm not sure if this forum is correct for a Pokemon topic, but screw it. Pokemon is anime.
Anyway, I have been looking at the ending to the 5th Pokemon movie (Heros) and I have made up my mind about who kissed Ash.
I believe it was really Bianca. This is proven by the fact that, during the early portions of the credits, Ash, Brock, and Misty see Latias and two Latios flying back towards Altomare. This leads me to conclude that Latias wasn't even in the city when Ash was leaving Altomare, therefore, Bianca was the only one of the two who could have kissed Ash.
Anyway, let me know what you think of this argument, because I am willing and ready to debate.