Art Fighting

What's the best martial art/fighting style for fighting much larger opponents?

I have practiced Tae Kwon Do, Kickboxing and wrestling on and off for about 25 years now. While I feel confident in fighting someone that is about my same size, I would be very hesitant to fight someone significantly larger than me. Does anyone have any opinions about what styles of fighting are better for fighting opponents that are 50 to 100 lbs heavier than you?
All of these answers are very helpful...thank you all very much. I guess my biggest concern is a much larger opponent simply bum rushing you and taking you to the ground. If he out weighs you buy 100 lbs, you are pretty much SOL. So I was thinking Ju Jitsu might be the best in that situation. Any thoughts?

Wing Chun is a very effective fighting style for larger opponents; it's primarily what it was designed for. A woman pioneered it as a style, so it's ideally suited for smaller, lighter opponents to fight successfully against larger and stronger ones.