Which substrate did you have in mind? I have a really fine sand in the predator tank, which are great for my two Wrasses. Though I wish I would have went with the Fiji Pink, not as fine, but would have worked, and not as easy to kick up. In my community tank I have Tahitian Moon Sand( black). It's definitely an interesting substrate. I have mixed feelings about it. I like the whole being different factor, but I I only had one tank I would go with a white sand. It gives the tank a less tropical look.
Maybe when I paint the background black it will mesh the tank better.