I'm not gonna break down the generations this time. I don't mean to come across as a genwunner, but given the sheer number of entries for each generation, Gen I just has the most quality Pokemon without filling many (if any) slots with trash. Even Generations with higher highs have much lower lows, and usually more of them than even the worst of Gen I (which is Golbat, by the way).
Touch fuzzy. Get fuzzier.
Inviso