Purely from a cost/benefit perspective, I'd want a novel or graphic novel first. The other media require plenty of cash to get going, hence the risk is bigger, so the likelihood of it happening any time soon is much smaller. In contrast, a novel wouldn't take much to get completed in comparison to the other media in the poll.
I'd honestly prefer a non-graphic novel, not only because it would be most feasible first option, but because I feel it would complement the music and the band. Think about it - a novel plays out in your mind, a kind of dream theater if you will, and is one of the best mediums for telling a pure story. We will already have the album, a medium that realizes emotion through music. Sure, the lyrics will tell a story, but I'd imagine for most of us, we're primarily listening to the music first and lyrics second. A novel would reverse this by putting the story first.
It would be pretty cool to have the music echoing in my mind while reading the novel, and once done the novel, appreciating the album, in particular how the story drives the music, in a more meaningful way.