1st gen:all the starters were great from this gen. Though Venasaur was always my favorite. Imo Vena>Stoise>Zard
2nd gen:Pretty Good designs this gen, but not as good as gen 1. Still Meganium was always my favorite(even if Meganium sucked). Always found Feraligator's design to be pretty meh. Meganium>Typhloshion>Feralligator
3rd Gen:Blaziken looks cool. Swampert looks kinda meh. Sceptile is ok design wise.I picked the grass starter in Sapphire and I had high hopes for Grovyle looked like he was flying in the air in his sprite. I thought he was going to evolve into a badass dragon/grass or grass/flying. I was a little dissapointed he evolved in Sceptile.
4th Gen:Loved Empoleon's design. Torterra was really cool too. Infernape had good design too.
5th Gen:Probably the weakest starter designs in the series. Serperior looked cool but was a lousy starter. Embroar's design isn't that bad. Didn't care for Samurrott.
Infernape took the golds because he was demonstrably the best starter, and the only easily accessible fire type in the fourth generation until Platinum aside from Ponyta. Though I did like how DP effectively forced a lot of people to use Rapidash, as a huge Rapidash fan. Wheras Swampert easily matched Blazekien's repute, and I have heard far more disdain than praise for Emboar, I don't know what you're talking about.
I'm grass starters all year errey year, have never picked the other two for a first playthrough, and I can tell you they are the ones everyone forgets. Usually with good reason.