Bumping this. I have an old dog eared Yellowstone travel guide from our 2010 trip along with several hard copies of maps. We'll do the normal stuff like Mammoth Hot Springs, Old Faithful, Grand Prismatic (but from the Fairy Falls trail overlook), Upper and Lower Falls. What I am curious about is anything that might be outside the general park that would be interesting. 95% of our 2010 trip was spent at the main highlights. LTBear gave me good tips some of the wildlife spotting areas.
One thing in particular I was curious about was Cave Falls and Bechler Falls on the far SW side of the park. Obviously, these two are very different because of their width rather than height. But it looks like a good day trip without lots of people. Personally I woud love to go even farther on to Dunanda Falls but my group won't be interested due to the distance.