I'm on the same page with you. I saw it opening weekend, so it's not too fresh in my mind, but I was a big fan of it (and, like you, all of Nolan's work).

I would have preferred if he hadn't ended the movie with the top gimmick, because I don't think it was necessary. I get what he was going for, but I don't think he needed to do it.

Personally, I don't think the top falls. It already spins for too long by the time the camera goes to black, IMO. I don't, however, think that the whole movie was a dream. I just think he ended in limbo.

For a discussion on the meanings of the top, I like this review on Aint it Cool.

There's also an interesting analysis of the spinning top from a scoring standpoint.

And I think my favorite - and the most straightforward - summation of the spinning top was a one sentence quote I read on Boing Boing:

"It shouldn't matter to you whether the top stops spinning, because it doesn't matter to Cobb."