With the exception of Gen V, the fire starter is the best choice in every generation. No gen gives you access to a decent fire type besides the starter for the beginning until a decent part of the way through. Maybe gen 1 is an exception to that but not really. Grass types either aren't relevant or have a good availability, and water pokemon are easy to come by, because of this guy. This one pokemon for four generations makes the water starter completely irrelevant because if you're hard up for a water type, this guy is always available, and available quickly. Don't want him? There's still usually other water options.
That's not true with Gen V. When they replaced magikarp with basculin they finally made the water starter relevant.