Wow. For some reason, the thumbnail of this didn't strike me as being anything spectacular, but this is dramatically corrected once seen at "full" size. It's just a GREAT sky, and the sharpness of the details of the trees in front is great. Concur with Toni on the clone-tool useage on this one.
John, I like everything in this except the little part of the sun coming through the trees down right. It need to be large enough to really recognize, or I would clone it out. It really pulls the eyes down to it, taking me away from the beautiful sky. Clone it out on another one, and see what you think.