There sure are a ton of answers to this. I'll nominate Splash Mountain.
Most guests are drawn by the weenie appeal of the large drop and the screams, but once they board the ride and experience the detailed dark ride portion that's where the magic really happens. There's tons of dialogue and music to hear, and it's impossible to hear everything on one ride through (unless you get stuck at the bottom of the big drop or at unloading), which is a neat trick Disney Imagineers use to make multiple ride throughs unique. Add in the fourth wall humour of the vultures at the base of the big drop ("Time to be turning around... if only you could!") and it really beats people's expectations when they think it's just a log ride with a big drop.