One of the main things we get asked when someone is looking to buy a wall mount is how much will it make my TV come away from the wall? Everyone wants the screen to be as flat to the wall as possible. We mounted a Samsung LE40R73BD LCD TV the other day using this bracket as it's just 40mm in depth:

It's best to have a small gap behind the back of the screen anyway as it allows air to circulate. Also, when your looking directly at the screen you really can't tell how far it comes away from the wall very easily - it's only if the tv is mounted in a location where you will be looking at it sideways where it will be noticable.