Over the weekend my wife and I went to see How to Train Your Dragon. Holy crap. It was really good. For the type of movie that it is, I think it was just about perfect. Coming from me, that's saying something. I can pretty much always find something to complain about.
Not only was the movie great, but the rendering went above and beyond! I was expecting the fire to be the impressive rendering feat, but it was the water and the clouds that impressed me. Of course, it is hard to top the fire from The Half-Blood Prince. I think the best shot was towards the end of the movie. The Vikings had arrived at an island by ship. One of the dragons was going breathe fire over the ships. The camera cut to a shot from under the water looking straight up. It's hard to explain, but it was freakin' cool. It's about 3 seconds after the image below.
And yeah, the fire is pretty damn sweet in that shot.
About a minute into the trailer are some good shots of the water (surface of the lake) and the clouds.