Sherasi just posted a great cleaner for streak free windows.
Sherasi's post

Now that I know what to use, how do I wipe the cleaner off? I have tried newspaper, papertowels and cloth towels. I always end up getting streaks and have to wipe it over and over again. It is never quite clean enough. What works best?

My mom swears that an old linen kitchen towel is the best for windows. You also could try a chamois cloth, the kind that car detailers use.

hm clare newspapers always work best for me. I know it is hard finding something that doesnt streak though. Its not like I clean windows a lot but when I do I want them with no streaks. Other than shers cleaning solution which is wonderful I am sure have you ever tried those windex cloths that are pre-moistened? there is no need to do anything but wipe down the window and let it dry works pretty good for me and they work really great on mirrors too.