Acrylic enamel paint is what you want as opposed to a lacquer (it dried hard and is not as easily chipped). Spray or roller it doesn't matter.Just remember to do it in multiple light coats with drying time in between each coat for a good job. I used a low gloss black applied with a small foam roller and it came out very nice and I didn't make a huge mess.
To make the sure the paint stuck to the glass I prepped it with a product called ESP- Easy Surface prep. I purchased it from Bunnings.
www.floodaustralia.net/products/esp.htm
It provides an invisible bonding surface for the paint to adhere to so it won't chip or flake if applied correctly. The way I did mine though means its on there for good, so if I change my mind about the background (which I won't) it means buying a new tank.
A couple of pics of mine just to give you an idea..
Also I find the gloss doesn't really get too reflective. I have never scrubbed the back panel of glass for algae since I started the tank, the black paint hides it very well and my Pleco must be cleaning it at night.