Red, Blue, Yellow, Gold, Silver, Crystal: Kanto - Bulbasaur (Brock and Misty, good match-ups for the beginning) Johto - Cyndaquil (Bugsy has a good match-up)
Yeah Bulbasaur was a good choice in Kanto,I always took Charmander and had rough starts against Brock and Misty. I always had to spend time training a Butterfree or something for those gyms. Charmander is worth it later and Charizard was always my favorite Pokemon so I usually did ok.
Kanto - Charmander (I always liked him best despite his disadvantages in the first two gyms) Johto - Totodile Hoenn - Torchic Sinnoh - Chimchar, though it was a difficult choice between him and Piplup (I love penguins)