Unpopular opinion here: I think Gen I did. Gen I, as a whole, wasn't that great in terms of Pokemon - most were just existing animals with contrived elemental motifs (or, worse, without them) and didn't seem that creatively designed. The starters, of course, were no exception. They all had similar-looking faces, which was a little eerie.
I'm surprised that Gen II is getting so many votes and Gen III so few.