Deathdrop,
Xenomorph,
15 years ago
Never say never, but it seems like AvP is finished. As for other sci-fi, just about everything has been done. The next place sci-fi in general could go would be some sort of posthuman deal, but A/P are dead as "new" concepts.
Sci-fi can be held over for now with the Superhero movies, but they'll overstay their welcome eventually. Something new (or something old in a new way) is what's needed (and lacking) in current sci-fi.
As much as I enjoyed Cloverfield and Star Trek, they were basically retreads.
Cameron's "Avatar" seems like it might be an original take on the whole alien planet idea, though, so we'll see.