Sorry for the short post gone long
I picked Charmander, since when he evolves to Charizard, he permanently shuts down the ground weakness except for one that slipped off my mind while writing this, but for the other generation I choose Mudkip entirely. I mean, Mudkip evolves to a powerful pokemon, unless you hate his weakness for grass, which hurts when he gets them. Torchic is very good too, especially in his third evolution. Torchic would be my second choice after Mudkip.