With the grass type starters my liking of them tends to decrease as you go across the generations. Bulbasaur is my favourite starter, as Venusaur is really cool. Chikorita is just as good. Treeko and Grovyle are really great Pokémon design-wise, but Sceptile ruined it for me. And finally Turtwig is just lame like all the fourth gen starters, so it's my least favourite.