The more I see of Mega Evolutions in Pokemon X and Y, the more I like 'em. As a quick refresher, these can only occur during battle through the use of Mega Stones, so the transformations aren't permanent. Which is probably for the best, depending on how crazy Game Freak gets with the existing Pokemon roster. This could get out of control, fast.
Currently, there's Mega Lucario, Mega Blaziken, Mega Mewtwo, Mega Mawile, Mega Absol, Mega Ampharos, and Mega Kangaskhan. I was never the biggest fan of regular ol' Lucario, but damn if the new design doesn't appeal to my inner 12-year-old, Digimon-loving self. Got any specific Pokemon you'd like to see turn Mega? I'm itching for Feraligatr to go full on Godzilla.