I went ahead and saw World War Z yesterday, and it was entertaining enough. The plot was the same as any plague-genre movie. I mean EXACTLY the same, scene-for-scene. The differences were in the details and the scale. Several things happened that I didn't expect, which alone is interesting. I haven't seen "zombies" animated in such huge numbers before, or with such unique collective movement.
The movie changed sharply half way through and became a different film. New plot, new cast, everything. It's like it was two episodes of a mini-series stapled together. The transition scene was entirely unbelievable, too.
It ends just as you would expect, with one guy having one brilliant idea, which could never really work, but which immediately results in a "cure" that is sent all over the world next day, in exactly the way medical discoveries never happen.