! Inferno Lord Z
Rawr. Me scary Resh.
Suicune, because it got its own version. None of the other beasts did. Besides, Suicune's design is nicer.
I like Suicune. Its design is very sleek, and Ice types are my favourite.
In addition, since Crystal was the first version I ever played, Suicune was the first Pokémon I knew about. Of course I had heard about and seen pictures of Pikachu and Meowth, but overall I was generally clueless up until about five years ago.
Entei because of Pokemon Movie 3000.
Suicune a close second because of Pokemon Crystal.