Seeing it in 2D either way. 3D is still a gimmick to me and one that isn't even very good.
To me 3D is only worth it if there is a movie done in 3D and first watched in 3D. Then in a second viewing you see it in 2D and you think "Man it just wasn't the same without 3D".
If Avatar didn't do that for me I'm not sure anything will. The movie was no better or no worse in 2D.