Chud.com has been doing a lot of coverage of Inception for the last couple of weeks. I didn't read any of it until last night cause I didn't want any spoilers. Anyway, Devin (who I normally dislike because he hates on many things for no real reason) put together a final article commenting on the meaning of Inception this morning. Here is the link:
I think that Devin is right that the entire movie, every frame, is a dream is a stronger argument than just "he didn't wake up at the end". I also like the idea that the whole thing is a metaphor/whatever you want to call it for movie making and that a catharsis in a movie/book/other media is just as good as a "real" catharsis is a fun point of view. And this helps make a little more sense what I thought were a couple of very pointed lines - when Cobb (diCaprio) says "no, I believe that a positive emotion resonates stronger than a negative emotion" and his other couple of lines about catharsis. Again, i will want to see the movie again before I will really come to my decision on what the movie says, but it has all been a great ride.