say what! wrote...
I would choose a dark type because they are always reliable.
This. If a specific one, Houndour.
But, due to current restrictions, I usually go with whatever is cutest. In B/W I went with Smugleaf.
Off topic: It irritated me to hell that they made it so that you're at an automatic disadvantage for the first gym. Yes yes, they give you something that will work, but I never really liked using the little monkeys. I'd rather have leveled my starter than a pokemon that I used for one gym then shoved in my box for the rest of the game.