PLOT SPOILER WARNING.
Ending
[details=Spoiler]The way I see it is, Cobb is clearly not in limbo because there’s a definite time when he wakes up on the plane. He wakes up to see everyone else, content to have completed their mission - with the exception of Saito, who looks like he just woke up from a very long dream lol.
Also, if we consider that Cobb is on the same “dream” level (reality) when he sees his Totem fall as he is when he sees his kids, it doesn’t make sense to believe that previously the Totem fell and now that he has seen his kids, it won’t fall. Again, that assumes Cobb never enters a dream state between waking up on the plane and seeing his kids.
Something else I noticed is that you never see the kids’ faces all throughout the movie until the last scene. Any other time, their faces are hidden or obscured - my interpretation of that is that it’s either because he’s dreaming and they’re not real, or Cobb’s subconscious guilt at not being able to see his kids again makes him literally unable to see his kids (i.e. see their faces) in his dreams. Yet, at the end of the movie he is able to see them, plus we the viewers, are finally able to see them. So that’s another reason I think the ending is real.
My feeling is, Cobb couldn’t possibly be in Limbo when he sees his kids - if he were, we would expect one of two scenarios: One, he is in Limbo and is back in the same Limbo he was in with Mal (and later showed to Ariadne). We’ve seen that Limbo dream and know what it looks like, plus, isn’t it crumbling and in disrepair? I don’t fully recall on that part, so someone correct me if I’m wrong. Anyway, the other scenario would be that he’s in an entirely new Limbo state, which would start him with a clean slate, which would have required him to recreate all of the environment, which he didn’t do (or at least, we didn’t see him do it).
Lastly, if we are to believe that they were never in “reality” to begin with, that would mean that Cobb is dreaming on his own, which would mean that every member of his team is a projection. That seems pretty implausible given their unique insights and talents, many of which Cobb does not share (especially Eames, the impersonator, and Yusuf, the chemist).
So, bottom line, at least in my opinion, Cobb gets to see his kids. Happy ending.[/details]
But man, I loved this movie. I would watch it again if someone invited me, and I am 100% getting that shit on Blu-Ray when it comes out.