Tepig. I've long been only choosing the Fire type starter, save for Snivy in White 2, which I never got to really finishing. However, if I had not transferred that Snivy up to Gen VI, I would have probably chosen it in ORAS, cause I just love its design so much :)
But yeah, I've been contemplating on breaking my habit of only choosing the Fire starters lately... I definitely wouldn't have started that with X and Y, because Fennekin is far and away my favorite out of the Kalos trio. But I couldn't help but feel that, since I have all the previous Gen fully evolved Fire starters moved up to ORAS, I would have benefitted a lot more from choosing a different Unova and Sinnoh starter for once...oh well. -_-