gen I isnt a contest- venusaur easily has charizard and blastoise beat, even though I like all of them.
gen II is pretty close between meganium and typhlosion, with feraligatr miles behind both of them. meganium wins out tho.
gen III isnt a contest either- swampert easily takes it home from blaziken and sceptile.
gen IV is tougher, as both torterra and infernape are among my favorite starters. torterras still the cooler one though.
gen V is tough because I dont like any of them. emboar is just lame, samurott would win if samurott had actually looked like oshawott and dewott, so serperior takes it? I guess?
gen VI is again super cool starters but chesnaught is miles ahead.
gen VII is one of those cases where I again dont like the starters, but incineroar barely wins over primarina. decidueye is straight-up the worst starter in pokemon existence though.