i'm in your conscience
Although FRLG are 3rd gen games, I consider those Pokemon gen I Pokemon, so I'm only considering those introduced in gen III. Anyway, my favorite is Regice. I love that trio in general, I love its cry, and I love the way you get it. Well...waiting is a bit of a nag, but at least that was changed in Emerald. It's also got a nice shiny color!