I don't get this whole 3D movie thing. I saw Coraline in 3D and the 3D-related gimmicks were slightly amusing, but it was hard to watch. I don't mean that in an "it sucked" way; it was a great film; it's just that seeing it in 3D was physically taxing. It made my eyes sore and very tired, and for those few slightly amusing gimmicks it wasn't even close to worth it, even if the 3D version were the same cost as the 2D version (which it was not) and you didn't have to wear horribly uncomfortable glasses.
I saw Avatar this weekend, and despite my inclinations, I saw it in 3D, on the raving recommendations from friends. My experiences were the same as with Coraline. There were a few neat effects, like sparks and ash that seemed to float in front of the screen, but it just looked awful and blurry, as if I had my contacts in the wrong eyes, and I had to keep looking away for a few seconds every once in a while to "reset" my abused eyes. I was even in a prime seat near the center of the theatre. One movie in 3D like that in my lifetime was enough, I think. I'd rather just see the 2D versions of things. If either Avatar or Coraline weren't quite as interesting I'd have just left the theatre and asked for my money back.
I'm willing to believe that there are people with certain eye characteristics for whom the 3D effect just doesn't work properly—there are, after all, many people who can't see a "Magic Eye" (autostereogram) properly no matter how hard they try. I don't taste artificial sweeteners the way that normal people do. And the sound of that a CRT TV that's turned on but just displaying blue makes drives me mad but inaudible to most people. Maybe some people just aren't meant to find the 3D effect enjoyable.