I have a combination in most of my set-ups. I am not as completely useless at keeping live plants as I thought I was, but it still takes a lot of effort on my part not to kill them, so I supplement with fake just to get as natural a setting as I can. Later today, I am getting a 55 gallon that I am setting up as a terriarium for my geckos, complete with rocks, driftwood, hides, real and fake plants, ledges and watering "holes". My toads are in a completely natural setting; my African Bullfrogs have the most boring-substrate, moss, and a soaking dish.