Well, the "big one" was what I referring to. I think any of the twists are telegraphed, and I found nothing in it particularly surprising (definitely shocking at moments though). But Palooza already summed up what is great about the movie anyway. Like I said, I love the movie, but I think that it's overrated.
EDIT: maybe twist is the wrong word for a lot of what happens in the movie. I consider the major one to be really the only one, because to me it builds itself to a reveal. The other reveals are simply an instance of "this information hasn't been revealed to the viewer yet".
It's really hard to talk so cryptically about this.