Fourteen more 3-D movies are scheduled for release this year, including Harry Potter and the Deathly Hallows, which Warner Bros is also converting from 2-D.
In a blog post today (subscription required) Greenfield points out that despite Warner Bros. heavily hyping The Green Lantern in 3-D on Fandango, the film still seems to be selling more 2-D tickets.
The difference between Potter and something like Clash of the Titans (also a Warner Bros. movie) is that filmmakers will have had almost a year to perfect the 3-D effects on Potter.