I'm not so sure that 3D is the right way to present a new Alien film... it relies on too many scenes where images need to "pop out" at you. It works in your basic horror movie, but this film needs to be something a little more than that. Then again, I havent seen Avatar so I cant really judge Camerons new technology. This isnt a stupid topic by any means, but it can be discussed more thouroughly once we've all seen Avatar.
And 3D isnt a stupid gimmick. Its a classic format dating back to when your parents were kids. I still like 3D movies, but I'm not so sure that I want a Ridley Scott Alien movie to be done in that format.