To clean windows streak free even when the sun is shining on them try an E-Cloth from Lakeland. They are wonderful. You only need water and the cloth to do the job. It also works on any glass surface and shiny metals. I wouldn't be without mine
Windows - vinegar in warm water, works a treat. Dry off with a clean, dry cloth.
Stainless steel worktops/sinks - vinegar and bicarbinate of soda, mixed together it fizzes up and cleans. I sprinkle bicarb first, then pour on the vinegar.
My mother told me that, to clean windows, all you have to do is dampen some newspapers and wipe the windows with them.
But the 'drink the vodka' solution has its appeal as well.