I think treating your son as a bad experiment, trying to kill him, killing his mother, coming back and trying to kill him and kill his love interest pretty much makes David Banner the worst.
if you're bad enough to your own kin, then you have no real backbone.
I guess nomak also killed his siblings but he was more pissed off he was rejected so it was like being slightly emo.
everyone else on that list has at least one redeeming quality of loyalty, purpose, original family values or something.
Banner was evil before he got any powers....gotta hand it to him.
i know many will disagree but meh.
ultimately doc ock managed to save new york (apparently) while spiderman was flirting with his girlfriend. It was his tentacles that were actually evil and he was somewhat weakminded and easily manipulated. Meh
dafoe gets a decent mention for corrupting from beyond the grave, that's a tough talent to beat.