It's Aerodactyl, has been my favorite ever since I was a little kid. I really like the fossil pokemon, and that's something that's stuck with me through all of the gens.
Admittedly Mega Aerodactyl had a weak design, but I still rocked him in XY.
As far as Glaceon I am a fan, but I like all of the Eevees. It's too hard to pick a fave.