Wolf Creek may be the world capitol of tree skiing. The trees are far apart, you can go anywhere, any direction, (as long as you can handle double-black diamond) and not get stuck in thickets, not end up outside the ski area. Total freedom, and of course the legendary powder. Usually they get 1 or 2 powder days every week, and you can find soft stuff back in the trees for days after that too. As a bonus, it is rarely crowded, and everything is affordable too!