True, Pokemon gets boring because of that aspect, but to complete the game is whole other story. To complete the national Pokedex is not it. My idea of "finishing" the game is to get your trainer card to the highest color it possibly can. For FRLG, it goes Blue to Green to Bronze to Silver to Gold. For RSE, it goes from Blue(?) to Bronze to Copper to Silver to Gold. For DPP, it goes Red to Blue to Bronze to Silver to Gold to Black. For HGSS, it goes Red to Blue to Green to Pink to Silver to Black. For BW, it goes Green to Purple to Red to Silver to Gold to Black/White (depending on your game). Unless you haven't gotten to the top color in the game, you haven't really done anything yet.
And for the starter Pokemon question, there should be three evolve forms. Go on serebii.net. It should be there. I don't know which source you're looking at.