T.W.
We did our basement and our contractor came in and directed us on so many things that were just amazing as far as layout and optimizing space. Some of my favorite items in the space are a wet bar (quite small but love the water and fridge so I don't have to run upstairs when we are watching a movie), they also put storage behind our TV set up so it is not intrusive to the space and for the crafts and play area it is planned where it isn't a mess all the time. It is just wonderful!
We only had about 900 sq. ft. but it is all well used. We did not go green on anything just due to costs. The pricing worked out to be SO much more expensive when we looked at installing green products and materials. Wish I had more input there - sorry.
Good luck to you, it is fun to have a brand new space. Let me know if you want to contact our contractor, it was a wonderful experience with little brain damage.