Jesus, Willco, you'll pay to see fucking TRANSFORMERS and FANTASTIC FOUR 2 in the theater, and not Knocked Up or Ratatouille?
I don't see films alone in theaters. It's my rule of thumb. And I was paid for when I saw Fantastic Four: Rise of the Silver Surfer and Live Free or Die Hard. I also got a free ticket when I paid to see Transformers. It's just easier to get people to go to or be invited to event films rather than romantic comedies, children's movies and smaller flicks.
Also, considering the price of tickets these days, I'd rather spend the money to see these low brow, popcorn flicks in DLP with incredible digital sound - it's arguably the best thing they have going for them. Stuff like Knocked Up won't rely on theatrical presentation to make it enjoyable and I can buy it on DVD for the cost of one movie ticket practically.