I think that, until both movies' marketing campaigns start kicking, both have potential, for different reasons.
The SW movie has potential because the franchise is mainly based on a relatively short story, as told in the six movies so far made; many fans (and even not fans) will be interested if only because this movie will expand on the SW universe. Of course, there are countless comics, cartoons and novels, but these haven't been exactly as mainstream as the movies; and maybe, just
maybe, this movie might be considered as such.
On the other hand, DB amounts to
hundreds of hours of story, covering every basic idea or scenario (and sometimes over and over again, like the villain-turned-good-guy, or the finding a new, even wiser and more powerful fighting master from which to learn to fight the new, tougher villain), and the movie will have little chance NOT to tell a story that's already been told... even if they depart from the known plots -which, as already proven in these forums, might upset many fans to no end... my point is: on one hand, there's the undoubtable interest in a live-action movie; on the other, it's something of a no-win situation, because if they use a plot unchanged from the series, it'll have less interest to some people, whereas if they create a new plot that contradicts something already established, it'll anger some other fans.
Um... I'm not sure if I'm making any sense
