I loved, loved this movie. I was very impressed with the story and how captivating it was. I was on the edge of my seat for large portions of the film, and that's something that doesn't happen often. I loved the anti-gravity scenes, and gosh, is Joseph Gordon-Levitt the business. Also Cillian Murphy. I love me some pretty, awkward and lean men. Plus, the guy who played Eames is the same one who played Captain Picard's clone in Nemesis. I liked the corporate espionage angle (because honestly, sometimes the good guys in movies are the bad guys, and vice versa, but that doesn't mean they can't be sympathetic characters).
The twist ending thing... I talked to J. Wes about this because I typically really dislike twist endings. What I felt they were trying to establish with the top spinning (it looked like it was about to fall over, but did it?) and with him finally seeing his children's faces is that it doesn't matter whether it was a dream anymore.
It could be real - Saito shoots Cobb, then himself, Cobb finished the job, got off the plane, and gone home to his children, happily, and they just cut before the top fell.
Or it could be a dream, Saito shoots himself, and leaves Cobb, and he can finally see their faces because he's gotten rid of the guilt for his idea leading to his wife's death. The top keeps spinning.
The big thing though, is that he walks away without even caring. Yes, he pulls out the top and starts it spinning, but he sees his children, and he sees their smiling faces, and that is all he needs. This is his reality. He's left behind the guilt and he is where he wants to be. I thought it was a nice ending.
TGW noted that in the shot where Cobb starts the top spinning at the end, you can see a sleeping female form in the shot, but I didn't see it (he's more observant).
Overall, it was a great film with great effects and I'm pretty entranced. I love the ideas. My head is all twisted up with them!