I've got a similar tank to that and what you can do with them is endless.
Have a think about what sort of environment you want to create. If you want a modern zen like thing going on get either white or black gravel or mix both in to patterns. Red Plants also help with this look. At Pets at home you can get Simple ornaments or have a good scout about on the internet can trough up some interesting ideas.
In my tank i wanted to for a typical thing, skull (The little fish love it), Bog wood, and a resin ornament which looks like a mangrove root. For my back ground i got one from the LFS in all fairness now my plants have grown i don't really notice it. I am thinking about saving up and getting the 3D Juwel backgrounds.
Here are a few pictures of my tank... Pleas bear in mind its not the best looking in the world but it might help.