Windex will definitely damage LCD screens. Never use it or any other window cleaners.
The double microfiber cloth solution can't be beat for price, simplicity and eco-friendliness over the long run.
In the computer department, you can buy packages of LCD specific wipes that are much cheaper than Monster's who would have you believe that their product needs to cost more since it is for home theater instead of a computer screen. But again, why not get a permanent solution in the microfiber cloth.
However, the wipes do have their place if your kid has smeared something particularly sticky or crusty on the screen. The chemicals in it will help to break down the crap better than a damp cloth. The trick is to do it without rubbing the crap to the point it scratches your screen.
