Gotta vote Meganium as the worst starter. I can see myself picking any starter at least once but not Meganium. It's move pool is pretty bad and the region it's thrown into is bad for it. Bad against the 1st, 2nd, 4th, 6th, 7th, and 8th gyms. Also, Koga, Lance, and a couple of Karren's pokemon will make it ineffective. It's just not a fun pokemon for me to ever pick up.