And I sorta still loved it. Lots of plot holes and bits I don't quite follow but bar the first 45 minutes being pretty much pure exposition I still think its pretty awesome. Takes itself too seriously yeah (and not sure why they have to resort to guns for their fights) but very good.
So I think I've figured out the possible endings:
1) The film plays out as we see it, Cobb returns home and is happy. Totem looks like its starting to go, kids are a bit older, he's not got his ring on for that last scene.
2) He's stuck in limbo but happy so thinks, fuck it. You hear the kids say 'lets go build a house by the cliff' I think...?
3) He's still asleep in that hospital in a deep sleep. We never see him spin the totem to check. I suspect Saito is drawing a moustache on him with a felt tip right now.
4) It was all a dream. Literally all of it, but don't think that works. He uses Mal's totem though and surely he shouldn't as its not his, meaning is it reliable? Also, MAL?!? That's French for Bad, innit?
5) Im not sure about this theory, but was Mal right? Did she get out and is he still in there? Why is she on that far balcony? Why can't he picture his own kids faces? Is her presence in the dreams actually her trying to get him out?
Any other crackpot ideas? Is getting home to his kids an idea planted in him by Caine and Paige? Why is Saito old and Cobb not? Are we in The Matrix?
I suspect the point of the film is to just make you ask the question and say 'well if it makes you happy, accept it' but its fun trying to work it out, eh?
Tl;dr Help me out Danielkelly / Guntrip / Theo / shucks