I'm not a huge fan of South-Western/Montreal Quebec-French accent. The further east you go in Quebec, the better the accent sounds, in my opinion. That being said, I still like it more than the Parisian French accent, that accent grates on my every last nerve. (Mind you, my friend that can do it probably exaggerates it just to drive me nuts.)

As far as English accents go... I'm not sure there's any that I really despise. But then, I'm not that familiar with all of them.