Charizard. I very much like reptiles, dragons included. I find Charizard's design to be quite clever and effective in portraying this Pokémon as a whole. Charizard is one of those Pokémon which stands out from the others to me. It (and Rayquaza) are actually my favourite out of all the Pokémon. Their shiny forms are also extemely cool in my opinion, unlike what others seem to think.
But anyway, I've liked Charizard for years, and the Pokémon itself really means something to me. Intrestingly, it's also the Pokémon I find easiest to draw, while still coming out well.