Vinegar is a wonderful glass cleaner. Combined with ammonia, it cleans better then any glass cleaner I have ever bought. It cuts through the toughest grime, and dries quickly. It also works well on mirrors. The next time you take a shower, your mirrors won't fog up.
Ammonia is a great cleaner in general.
When diluted it makes the perfect degreaser, and cleans greasy fingerprints up like nothing I have ever seen. Just remember to use it in a well-ventilated area. When I use it, I combine it with a small amount of liquid dish soap to mop on my no wax floors. And because it can leave a harsh odor behind, I take orange peels and some cinnamon throw in some water put it in a small saucepan and let it simmer. It leaves behind a wonderful scent.