I use Meguiars window cleaner, I think it's the best!!!
But even then, sometimes that can leave streak marks which you notice when the car is fogged up.
Here is a rule I have in my car - DO NOT TOUCH THE DAMN F*CKING WINDOWS!!!
hahaha
its even worse when people lean on them, cos their hair grease, or hair product is left on them.
But so long as you know if you have tinted windows dont use newspaper to clean the inside
Or, buy some glass cleaning wipes, they work well too... I like armour all for them.