As we don't currently have banner art I've decided to go to the community. The community decides the winner by upvoting the banners they want to see. It doesn't matter if you're amazing at art or not we welcome all artists. Now get out there and create your art! It will end in a week.
Whatever wins, just be sure to scale it down to something suitable. I've seen mobile users particularly complaining that some community banners are stupidly large files that eat through data.