As soon as the whole Disney/Marvel mess was announced, there was talk of Fox doing a new Fantastic Four film. Of course I suspect that was a case of wanting to assert their current rights, but it has had me thinking.
The second recent Hulk film was sort of sequel, sort of reboot. There's talk of a new origin-of-Superman film. A new Fantastic Four Movie doesn't seem unlikely. We just had a GI Joe movie.
I've wondered if the recent rush to superheroic/SF-ish movies, the desire to maximize properties, and the fact only some of the big superhero/SF/nostalgia properties have big name recognition means that past a certain point people will stop caring.