Your tank looks nice. Question though, why didn't you paint the white pvc? It detracts from the look of the tank. I would think that painting it black would make it blend in better. Or, if you are artistic, painting it in shades of brown to make it resemble a log would be neat.
Also, I don't really see a waterfall effect. You built the rocks up in the corner, and I was curious as to how you were going to make it work, but in your last pictures there doesn't seem to be any water dripping down there (actually, it appears that the water may be leaking out of the wrong side of the pipe...).