Starter Pokémon: Chikorita & Oshawott
Why would you like to join the club?: Starters are really awesome. Actually, all five starters are quite awesome. ^_^
Grass/Water/Fire is the standard three typings for starter Pokemon, but why do you think this is and what three types do you think could be used instead?
I guess they give you the option of Grass/Fire/Water, so that way the trainer playing the game can decide which is best to fight the first gym leader and beyond. Though I personally feel that Fire could be replaced for either Electric or Flying. But then as I think about it, both types are poor choices.
Ice is also a good choice for a water replacement. It'd be best for Rock-Type gyms. xD