Star Trek Online, Warhammer Online, Star Wars Galaxies, Age of Conan, Champions Online -- and the trend shows no sign of slowing. But there are other franchises that could conceivably make a number of people happy -- Transformers, The Dark Tower, Doctor Who, Mass Effect, Babylon 5, and so on ad infinitum.
Of course, there are licenses that are unlikely to ever be adapted for MMOs, either because their heyday of popularity has passed or because they're just not in quite the right market. Still, we can dream, and in our heads we might have an idea for the world's best MMO based off of Macross. What intellectual property would you love to have a chance to play as an MMO? Do you think there's a chance it might happen, or are you fairly certain that it's just going to remain an idle fantasy?