What a nice, simple natural looking setup. I love the tiny little plants you have on the bottom.
I also have the same tank, but 5gal I think. I wouldnt be too keen on de-rimming it though, especially if you have the filter hanging off the top.
btw... do you know if the tank is plastic or glass? When I bought it I was told that it was glass, but it feels alot lighter, and more like some sort of perspex (or however you spell it).