WOW, this is like deja vu. I was just talking to my friend about his car. He spends so much time babying his car and the paint(wax, buffing it atleast once every two weeks). He doesn't really clean his windows and when he wants to he buy stuff that says: "Streak-free" so he can fly through it. Well my point was and is relevant for this is: if you are always spending time to baby the car, why do you spend so little time on your windows, vacuuming, ect.
I use a glass cleaner that we use on all cars at work. Yes it leaves streaks but if you fold the towel and use one side to clean, you can use the other side to take the streaks away and make it look better than the "streak-free" galss cleaners.