I bet that's going to be beautiful! I put sand in my 20, and I love the way it looks. I wish I had thought of it when I did my others, because they're all gravel, and I don't want to freak the fish out by changing it.
As of right now, I have a moss ball, a little anubias, and the wisteria that I thought was Java fern in the 10. I'm planning on getting some more, to replace the plastic ones I bought initially. I'm all about live plants right now. I also just ordered a bunch off of Live Aquaria, that should arrive Wednesday :) I ordered them for the 20g, but may decide to stick a few in the 10. I love that layout on Tropica! Beautiful! I really like the different substrates they used. Good luck with your new garden!