Mesogogg. Also Thraxx. Mesogogg and Thraxx together make up thirty Zedd's. Not that Zedd wasn't B to the A, but Mesogogg was much more evil...er.

Mmmmmmmm I still have to go with Zedd. Mezogogg was pretty awesome I'll give you that and Thrax was good too but I'd say the only other villains capable of giving Zedd a run for his money thus far would have been Frax from Time Force or Darconda from Space. Even then those guys were seasonal baddies. Zedd was multi-seasonal, bad as all hell, and in the end was even able to rock some sweet country club attire
http://img339.imageshack.us/img339/3...anlordzedd.jpg

We're forgetting five very good bad guys: The Psycho Rangers