Without question, Expedition Everest.
The track-switching portions are good in theory, but take way, way too long to happen. As a result, the ride almost feels episodic in nature, and that's not something you should ever be able to say about a coaster. Then of course there's the stationary, strobe-lit Yeti, which is nowhere near as scary as the Abominable Snowman on the Matterhorn, despite the fact it's about four times larger!
The queue for EE, however, is extremely impressive. While the ride is a letdown, the attraction as a whole is a must-see because of the immense amount of detail put into the story. But should a queue ever be more impressive than the roller coaster that follows it? I think not.