The character of light from a south-facing window is radiant, even and bright cool white. It never casts a harsh shadow or direct sun. East light is fresh, bright, light white-yellow and makes long patches on the ground in the morning. North light is extremely variable, easy to exploit, can vary from light and moody, to ambient and fresh, to harsh and orange. West light is often bold yellow or orange, makes long and hot patches deep into a room in the afternoon and catches dust mites. Each aspect calls for different treatment, proportion and shading.
An individual and site specific approach to aspect, orientation, sun path and neighbours is important. I love to include more than two directions of light into a room. Windows and light give opportunities to make beautiful compositions.
Recycled windows take a bit of work (salvage yard trawling) and design skill to articulate them into an elevation, but are well worth it.
Otherwise, I love to design new custom windows with some rhythm.