The Fourth Doctor had some hilarious lines, though my personal favourite Doctor is the second.

And since I totally don't spend fragments of my time reading quotes from fictional characters on wikiquote... - oh, alright, I do - here are some comments from said two Doctors that are quoteable enough to... y'know, get on wikiquote. :P

Four (http://en.wikiquote.org/wiki/Fourth_Doctor) (I believe said quote features there!)

Two (http://en.wikiquote.org/wiki/Second_Doctor)

I will now slink off to read something that totally isn't about fictional characters on wikiquote... :P