Gen I:
Squirtle
Gen II:
Totodile
Gen III:
Treecko
Gen IV:
Piplup
Gen V:
Snivy
Kind of close to you. 
I pick starters based on my favorite designs and evolutions.
Can I pick Bulbasaur for every generation? 
I like the first two sets of starters and the rest have been more or less lackluster to me.
Bulbasaur > Cyndaquil > Squirtle > Charmander > Chikorita > Totodile > Everything else
My choices for Starter Pokémon:
Gen I = Charmander
Gen II = Cyndaquil
Gen III = Mudkip
Gen IV = Treecko
Gen V = Smugleaf Snivy
I always choose Charmander in the first generation games. I don’t know why, I just love its evolutionary line…until I get Jolteon or Aerodactyl, then it gets shoved into the PC Box…forever! (evil laughter).
- Squirtle
- Cyndaquil
- Mudkip
- Prinplup
- Tepig
As you can see i’m not a fan of grass pokemon, i just dont think the attacks are powerful enough…
Gen 1 - Charmander was my first pick and my favorite of the three base forms, but I like Blastoise the most of the final forms.
Gen 2 - Chikorita was my first pick and my favorite for being the only somewhat girly line of starters. 
Gen 3 - Mudkip was the one I picked when I actually bought the game and is my favorite of the three. But I like Swampert and Sceptile about equally.
Gen 4 - Piplup all the way because I love penguins. Empoleon crushes the other two in terms of how much I like the final forms.
Gen 5 - Tepig was the one I picked and it’s my favorite because I don’t like the faces of the other two. Also, the amount of complaining about Emboar being Fire/Fighting makes me defend him.
Gen 6 to have an amazing Grass starter so I can have picked two from each type for my first files, please.
I have only completely played through Generation 1 and 4 so I can only comment on those two.
Generation 1: Squirtle
Generation 4: Piplup
These are the three that are definitely my first choices per generation. I didn’t include the next two generations cause sadly none of them stood out to me like these three. I kind of like Snivy but I feel like it’s too much of a copy of Treecko.
You’re missing out Scott! 2nd generation was the best, and 3rd generation was an absolute class act.
I’ve played through every generation so many times. 1st and 2nd (and their remakes) at least a dozen times each. 3rd generation a few times. The latest two, maybe once or twice only. Every game is so goddamn good
I love water types, so I always went for water on the first playthrough!
I) Bulbasaur/Squirtle… too tough to decide
II) CHIKORITA
III) Mudkip…
IV) Oshawott
V) Tepig !!!