Well, I never was a big friend of villians, so I think it is quite an odd question xD
Nonetheless, I think

Derek C. Simmons

is my least favourite one.

I don't know. He adapted so many cliches.
His clothes were so obvious. It only would have been more obvious if he'd wore a Shirt with a print 'I'm the bad guy here' xD
Either way, the things he did were so illogic.
Like Helena said: Creating a new disaster to stop another.
(I know it isn't the exact quote, just my memory xD)
Why didn't he just poison the president.
Too easy for him.

It is my own opinion :D
Tell me yours in the comments \(^o^)/