Most times, it is the water starter. There is no one I dislike, Squirtle is still my favorite.
I also like the fire and grass starters and choose them when I play the games again.
When I played it for the first time, I had:
Gen I: Squirtle
Gen II: Totodile
Gen III: Torchic
Gen IV: Piplup
Gen V: Snivy
Gen VI: Froakie
Gen 1: Charmander
Gen 2: Cyndaquil
Gen 3: Torchic
Gen 4: Chimchar
Gen 5: Snivy
Gen 6: Fennekin
Obviously Fire. Though in Gens 3 and 4 it was close because I didn't like Blaziken or Infernape at a first glance. Then I ended up with them. But Emboar is just horrible, so Snivy got me that time.
Gen 1: Fire
Gen 2: Fire
Gen 3: Fire
Gen 4: Fire for Diamond, Water for Platinum.
gen 5: I've played all, I went grass first though, love snake Pokemon.
Gen 6: FIRE! HAHA! GO FENNEKIN!
I do love all the other starters though except one that is more overrated then Charizard. I'm serious. If I mention it my rep will be lowered instead of people being nice and asking why I don't like it
Gen 1: Squirtle-Water
Gen 2: Chikorita-Grass
Gen 3: Torchic-Fire
Gen 4: Piplup-Water
Gen 5: Oshawatt-Water
Gen 6: Froakie and Fennekin-Fire and Water (Got 2 starters in a trade but i chose froakie 1st.)
Tie between grass and water, but gass has too many weaknesses.
Gen I: Squirtle
Gen II: Totodile
Gen III: Treeko
Gen IV: Turtwig
Gen V: Oshawott
Gen VI: Chespin
Gen I: Charmander
Gen II: Cyndaquil
Gen III: Mudkip
Gen IV: Turtwig
Gen V: Oshawott
Gen VI: Froakie
Well I guess that makes 3-2-1 in favor of Water-type. Tbh, apart from Gen II where I just don't like the Totodile line, all the Water starters have been solid. Blastoise is epic and Empoleon is cool.
My starters are Firered: Charmander, SoulSilver:Cyndaquil, HeartGold:Tododile, Sapphire:Treecko, Diamond:Turtwig, Platinum:Chimchar, Black:Osawott, and Y:Froakie
Kanto - Charmander
Johto - Chikorita
Hoenn - Torchic
Sinnoh - Piplup
Unova - Tie between Snivy and Oshawott (I kid you not. Black with Snivy, White with Oshawott. Never Tepig.)
Kalos - Fennekin