My general approach: When I want to display forceful water, I stop the action. (That explains why I prefer your third image.) When I want to display the ambiance of gentle cascades, I blur the water. On rare occasions, I'll want to display a bit of the detailed action along with the blur, in which case I'll merge two images, one made using stopped action and one made using the blur.
It might be helpful to get an idea of the shutter speeds that produce the look you want. Of course that will vary depending on the speed of the water. As an example, with every waterfall I've photographed I've been able to stop the action at 1/800 and most with 1/500. That's with really LOTS of water flowing really fast. If you shoot increments of full stops, you'll probably be able to find an image that displays the style you like. If not you can blend two images.
I think it all depends of what effect YOU like Allan. I like the effect around 1/10 of a second when you get long silvery lines that you can clearly see in large magnifications, that would look good when printed large. I have experimented a lot with different shutter speeds and in PP the 1/10-1/15 is the look the I like (depending on water speed etc). When you shoot slower Shutter speeds than 1/10 the images tends to be a lot of white in the water with less details, faster than 1/15th you slowly get more individual details and shorter silvery lines until you freeze the action at some high shutter speed.
So we are back to the question what look do you like?