3D scares the shit out of me. Every time filmmaking has had a similar introduction of new technology, the art of filmmaking has taken a huge step back.
When sound was introduced, films suddenly looked the way they did in the 1910s, except for european films that didn't record sound on location, and Chaplin, who continued making silent films.
When color was introduced to combat the introduction of TV-sets (much like 3D is only a gimmick to keep us from downloading movies), cinematography was fell back to where it was in the early sound era.
Early cgi confined the camera to be still.
I've seen some of the recent 3d films, and I'm not impressed. It's not about headaches or feeling nauseous, it's about how limiting it is to the filmmaker, there are so many tools you simply can't do in 3d (handheld, selective focus, superimposition, and so on). It's like telling a painter he can't use certain colors, or telling a composer he's no allowed to shift time signatures.
As someone who's hoping to direct his first feature film in the next ten years or so, I really hope no producer will tell me i have to make it in 3d because "that's the only way to make it sell".