if your screen has a membrane (anti-glare coating), get some panel cleaning gel...
http://www.amazon.co.uk/Philips-SVC2...1&sr=8-1-fkmr0
does a really good job - no streaks. seems expensive, but lasts a loooong time as you only need a couple of squirts to clean the whole screen (going by my 42"). water from the tap contains elements that can ruin the membrane so don't use anything on it other than specially designed stuff!!!!