I would intentionally NOT read one just on the chance of someone not being carefully enough to spoiler code the right material.
Glad I didn't see the Letterman clip.
I stopped following this film closely weeks ago on purpose and I'm far from "the most excited person" waiting for this film.
I don't think TDK is the manna from heaven film it's so lauded as, good yes, and I have reservations about this one. I'll be seeing it Thursday at about 2:30pm though.