Two whopping 48 x 42" windows overlook the sleeping area (we like morning sun!), two 36 x 42" windows light up the kitchen area, and another window sits high on a wall by the future shower. The other six wee windows sit in a row between the two roof lines; they're designed to let in winter sun and let out summer heat.
After a lot research and hemming and hawing, we went with Jeld-Wen vinyl windows. Not exactly a natural material, but an affordable choice. We have "builders' grade" frames, but energy-saving Argon-filled glass. Home Depot had similar windows at the same price, but we found ordering from our local Loudoun Lumber offered us a color choice at no cost (lovely, neutral "Desert Sand") and free delivery.
Lessons learned: 1. Check, re-check, then triple-check your window order before placing it. We caught errors (color, lock, slide) on several window specs that we would have been stuck with if we hadn't read the order over several times. 2. Attention to detail when framing does indeed pay off! We took it slow when it came to framing rough openings to be sure they were level, plumb and the correct sizes. That extra time was all paid back when the windows went in so smoothly. 3. One person working outside and one person working inside can divide up the install effectively. Our first window took hours (or at least it felt that way); our last one only minutes.