My list:
Torterra
Staraptor
Aggron
Groudon
Dialga
Squrtle
Ivysaur
Charizard
Pichu (The one with a scruff on it's head)
Gallade
Porygon-Z
Reasons:
Torterra, Staraptor, and Aggron are the best Pokemon in my Diamond
Groudon and Dialga are my most favorite legendaries ever.
Squrtle, Ivysaur, and Charizard are my 1st, 4th, and 3rd (in that order) best in Brawl
Pichu is just CUTE!
Gallade and Porygon-Z are just AWSOME!