I like eddieitman's shot, but also agree with Frank. The blurred water can be very nice, but I've also seen some "stop action" water shots with drops frozen in space..very cool as well.
G-Mike has the right idea (and Frank suggested it as well)...try different shutter speeds. You might go as high as 1/1,000 or 1/2,000 to stop droplets and splashes.
Tripod for the slower shots...polarizer will slow shutter speed as Faldrax said.
Try a lot of angles. My limited experience with water falls is there is often a branch or something in the way of the perfect shot. Like with flower closeups, we sometimes get so concentrated on the water (or ?) that we often forget to take a close look through the viewfinder to see what else is lurking around ... only to be seen on the computer screen when we get home. Once you are set up look closely at the entire scene for other "stuff" that might detract. (Sure we can sometimes clone distractions out...)