The Top 5 Fastest Roller Coasters in the World:
100 mph - The Tower of Terror, Dreamworld, Australia
100 mph - Superman the Escape, Six Flags Magic Mountain, California
106 mph - Dodonpa, Fujikyu Highland, Japan
120 mph - Top Thrill Dragster, Cedar Point Ohio
128 mph - Kingda Ka, Six Flags Great Adventure, New Jersey
The only one I've been on is Top Thrill Dragster and it was pretty ridiculous. You feel like the skin is going to peel right off your face. So awesome.