Saw this a mixed crowd of comic and non-comic fans.  We all had pretty much the same reaction - average summer popcorn movie, slightly above average for comic fans.  For superhero movies I put it exactly in the middle of the absolute best (Nolan's Batman Begins and Dark Knight) and the absolute worst (Singer's Superman Returns).  I haven't seen Thor yet, but some of the group had and said it was about at the same tier of Thor.  Predictable plot (heavily influenced by Geoff Johns run on GL), but still a lot of fun moments.  Mark Strong (Sinestro) and Ryan Renolds (GL) were the only standouts IMO.  Regarding Blake Lively (Carol Ferris) for a possible sequel ... she could certainly look the part of Star Sapphire but I'm not sure how believable she'd be acting the part from her performance in this one.

I'd like to see in hardcover:
Avengers By Perez/Byrne (181-202)
Alpha Flight by John Byrne Omnibus
Excalibur by Claremont/Davis Omnibus Vol. 1

Shazam by Don Newton