Yeah, xrayjeeper, it's nice having the sand and gravel both... Especially if you are having a planted tank. Most plants do not like sand unless you have a base layer of fluorite or something nutritious, or unless you use a flourite sand itself. And then some plants do not like gravel because it is hard for them to anchor themselves. I also needed to have sand for my bolivian rams to mate, and also for the corydoras to sift. However, whenever you use sand it's important to get some malaysian trumpet snails, otherwise harmful gas and debris form under the surface.
I was also going for a yin/yang look. When I was first doing the layout, if you looked down on the tank, there was black side, white side, the dividing line was S shaped, and there was the white rocks on the black side for the eye, and black rocks on the white side for the eye. Looked pretty cool, but don't really notice anymore unless you are looking down at it through the plants.
Good luck though, glad I could inspire something.
Bones14: I recommend bolivian rams very strongly. They are probably one of the most unique and personable fish I've seen. I recommend nabbing 4 if you have a 50 gallon tank, they each require about 1 foot of tank length until they pair up. If 2 pair off, they defend only 1 foot of tank length, so you can then get another ram to try to pair one of the other 2... If you're lucky, the 4 will make 2 pairs, and you can watch their little dramas.
Lots of websites say they are more aggressive during the breeding cycle, and that's definitely the case, ESPECIALLY against other rams, but they will not injure another fish, they will only chase it off and mouth it... I have yet to see one bite another fish. It's actually kind of interesting watching a female Bolivian Ram
herd up 6 corydoras and push them off to the middle of the aquarium.