Charizard, Fire and it can Fly
Credit to the banner goes to Zzzdark of Pokebeach.
Anyway, Charizard is my favorite, wit Sceptile as my second.
For me, it's Charizard. Yeah it's overrated and and a pain to have as a starter because of the first two gyms, but it was my first Pokémon and it always had a cool design.
My favorite Water Starter is Swampert and my favorite Grass Starter use to be Sceptile, it probably still is the best Grass Starter ever, but I have grown very fond of my Torterra. It's such a beast and a great battler. It's speed sticks, but it makes up for it with great defense.