My favorite has to be Expedition Everest (yes, even with the busticated yeti!). I've always loved roller coasters, but with growing claustrophobia I can't stand the over the shoulder restraints. EE is pretty intense without having those restraints, which works great for me!
Worst is by far the current version of Imagination in Epcot. It's the only attraction that will actively make me angry after riding. It's just so nothing, such a waste of space and a decent ride system. Very very lame!