Waterfalls are harder to come by than I would've thought. I've been on many hikes where waterfalls exist, except they're always dry when I get there. The best hiking weather, warm and dry near the end of the summer, is not the best weather for waterfalls.
Most good waterfall pictures require the use of tripod or some other support for the camera. This is because you want the water to have a smooth look that can be achieved only with a slow shutter speed and steady camera. And to make matters worse, you have deal with the mist coming off of the walls and covering your lens.
The ground-level shot I have is a waterfall in the Adirondacks. It rained 3 out of the 4 days I was there. The other picture is of Niagara falls taken from an airplane.