I pretty much agree with Mr2, but a 10 gallon is kinda small, and putting an in-tank background can chew up quite a bit of space. twixt that, and the substrate, you won't have much room left for plants and fish.
I really like the way a painted back looks. I've used spray paint in the past, but recently did one with brush-on latex. I think the spray paint was much easier, and took less time, but the latex is better/safer for using indoors - took a few coats though.
I like black because it helps make the colors of fish and plants stand out, and most equipment is usually black, so it just kind of melts into the shadows, and doesn't detract from what you want to look at.