I put the blue background up also, all the other "reef" backgrounds look so fake. Also when you put the background on it makes a huge difference on how the tank looks....good luck
I guess I am a minority. I found a nice Hawian Reef background for my 55 gallon. I have always liked it.
I have seen many of the blue backgrounds, and they do nothing for me.
I had one on my 200, but I took it down because water always got between the glass and the backdrop. I don't have anything right now, but I might paint it if i move the tank or have the balls to endanger my carpet.
I currently have a blue background that I bought at the ol' LFS. If you do decide that's what you want DON'T get something that's double sided (two different patterns). Mine has a reef picture on the backside that comes through the blue because of the intensity of my lighting. Painting on a color is a good idea if your sure that's what you want. You will never have the problem of getting water between the glass and the background or 3 year olds pulling it off.
LOL Cap! Bu the way, don't be scared to paint, it's not permanent. With a razor blade ie. Widgett, it is VERY easy to scrape the paint right off of glass. Not to sure about acrylic though.