I played with every starter, since I am always doing challenges and restarting my games.
I usually choose the one I like the design the most in the first time I play the game.
Here is the type I chose the most in each generation:
1st Gen - Grass
2nd Gen - Fire
3rd Gen - I like the three, but I usually pick the grass starter.
4rd Gen - Grass
5rd Gen - Grass
About my gender, well, let's say I always take the female protagonist.