2 and 3 are my favorites, however I think I favor 2 because it seems like the tree is much sharper and I like the yellow with grey skies. With the more blurry tree and too-intense blue sky as mentioned, it drops a notch. The only qualm I have with #2 is that it looks like you pulled the clarity up all the way ( most notably on the tree ) so it's casting a shadow on the left side of the tree over the landscape that is miles away. I suppose this could be intentional and desireable to some for that certain effect, however, personally I'd try getting rid of the shadow with curves, lightening up the image and then just masking the shadow area trying to blend it with the rest of the landscape.