I picked Chespin because I happen to fall under the grass-type minority.
I was reluctant, though, because Chesnaught has a ridiculous amount of weaknesses while not being Breloom. Of course, the Chespin-line ended up growing on me, even if I did swap him out of the team a couple of times.
I was so shocked to find out that we could have a Kanto starter at the beginning, and I ended up doing the taboo thing by picking Bulbasaur, despite already having another grass-type. Not only is Bulbasaur my favorite Pokémon, but it was an invaluable part of my in-game team. As a Venusaur, it pretty much dominated every single NPC, and I remember vividly when my Mega Venusaur barely pulled through against Diantha's Mega Gardevoir.