According to the Times Online, Avatar, in addition to making people depressed, is causing movie makers to want to go back and upgrade their movies to 3D.
Now I can understand why. 3D is cool, and a number of the movies mentioned would have been awesome if done in 3D, but the fact is that they weren't. And regardless of the amount of computer jiggery-pokery that gets done, it's not going to change the fact that going from 3D to 2D is really easy, but going from 2D to 3D is very tough.
The movies discussed are action movies that relied on lots of special effects the first time round, and depending on how much of the computer models still exist, you might even get some pretty good 3D in parts, but the more everyday scenes with just people and sets won't have that advantage, and will diminish the effect.
Such upgraded movies will also lack in comparison to made for 3D movies. Avatar does 3D well because it was planned as such from the beginning, and this gave the creators new tools to use when composing scenes and designing locations. Upgraded 2D films will not have these benefits and it will show.
All this improving of old movies to fit with new technology is not unprecedented. Classic black and white films have had color added to them later, to a generally negative reception. One of Orson Welles last requests a few weeks before he died was to not let Citizen Kane be colourised.
Now before you go calling me a neo-luddite or what not, let me sum things up on a positive note. Great 2D films, like great black and white films are great because of the art that went into them, the direction, the design, the acting, the writing, all of it. No one denigrates Citizen Kane because it's not in colour (no one with sense, anyway), they praise it for its merits. And so to if movie making transitions to 3D as a standard, people aren't going to mock today's greats for their lack of a third dimension. They will still praise the stories, the art, the greatness for what it is. Movie makers don't need to go add the latest gimmick to their movies.
On a final note, let it be said that no one should be surprised that George Lucas is one of those movie makers who can not wait to do this, and to be fair to him, if he does, I will go (to episodes III-VI at least)