Gen1: Charizard and Venusaur were both quite the best of their types in there game as for Blastoise(I never choose Squirtle ever) I found there were better water types like Gyarados, Laprass of Vaporeon
Gen2:before HGSS Typhlosion was a beast with thunderpunch, in HGSS Feraligatr was a beast with Dragon dance. Meganium mehh
Gen3: I liked them all in there own way Swampert was a good dual type, as was Blaziken (in the time that there was only gen3), Sceptile was a speedy and had a nice movepool with dragonclaw
Gen4:Empoleon the first water/steel, I liked him very much Torterra the first Grass/Ground was a beast aswell, Infernape made the Unique types of starters perfect :/
Gen5: TBH I didn't like any aspect of it other then Samurot being a Samurai Pokemon....