Someone always says it eventually, so I'll be the guy this time. Hard to have this conversation without Devil's Cauldron at Banff Springs getting serious consideration. The drop-shot tee shot in the 15th (formerly #1) at Banff is also pretty cool for a par 4.
For sheer elevation excitement, Sugarloaf in Maine has a couple grand drop-shot tee shots (both par 3 and otherwise), Fox Hopyard in CT has a very steep par 3, and Green Mountain National in Vermont has a few, but I wouldn't put any of these in best-of-class category even though the elevation change is more significant than many others.