Nemesis is just so intense and the smiler is just so much fun. You have no idea where you are going.
My favorite of all time is Space Mountain in Disney World. It isn't the most high-thrill ride, but it is thoroughly and undeniably cool for its retro-futuristic vibes. Plus, that it's in the dark makes it that much more awesome!
Besides that one, I'm a big fan of Goliath in Six Flags Over Georgia and Bizarro at Six Flags New England. I really want to go to Cedar Point someday, though!
I have ridden on a few in my time and they are all good. But my favorite one is a Knox Berry farm. Of course as soon as I read this thread I knew which one I like the most but can not think of its name. Its short and you leave your lunch back at the loading platform. You go from 0 to 65mph in a few seconds then do a 360 and run up the run off ramp hang for what seams like for ever 90 degrees to the ground then run through the loop again backwards. Go through the station and up another run off ramp hang again 90 degrees facing the ground this time. Then you go down to the station and they stop you suddenly like when you took off so that your lunch is now on the back of the seat in front of you. Then they expect you to get up and walk off casually.
I wish I could remember its name!
I just remembered the name.
Mona Zuma Revenge.