I really like the feel I am getting on this one. I feel as though it is a dreamy effective HDR. I really like the greens and how the give off a magical feel and the yellow in the sky has a glowing feel as it transitions into a lighter blue and then a darker blue its nice flow in the sky.
What I would like to see is that the clouds had a little more detail they seem soft and there is blown out areas in the sky especially the yellow parts. The building is crooked so fix that. Also I am not sure if you know how to do this but in photomatix choose the ghosting method and select the area that you want and then you are able to select what exposure you want to use in that area. IF you select the - ev you should be able to get rid of that blown out area in the sky.
I know it sounds like a lot of what I think you can do better but this image is worth taking the time and correcting some areas as it has a lot of potential to be a keeper!!