One of the things I like about Comic-Con is that it allows studio marketing types to trot out some actually nice materials. They don't have to be generic giant head posters and they don't have to be in the dominant visual idiom of the moment (backs to the camera!). They can just be a strong image that actually gives a sense of the movie.
Like this teaser poster for Oz the Great and Powerful. It's painted, which already puts it miles above other marketing materials. And it has a sense of whimsy and magic that I hope reflects what we will see in Sam Raimi's film.