Needless to say, if you're willing to go out in public in a TARDIS hat, you're a proud enough Whovian that you shouldn't be afraid to show your love on your walls. You can go with official posters like the ones on ThinkGeek or at the BBC Shop. However, there's a ton of really cool fan made stuff on places like Etsy or For Human Peoples. You can even have the Eleventh Doctor or Amy Pond on your wall. I'm a wall decal now, wall decals are cool. That being said, there's something for everyone.