Dang, I've seen Babel before too. It's a good movie though, so I'm glad to have a copy. Had no idea it was by Inarritu.
The plot(s) are too convoluted and intertwined to describe here, suffice it to say it's a series of journeys which leave the viewer both wiser and kinder than before. This is in marked contrast to, say, No Country For Old Men (or even Biutiful for that matter) which throw a lot of ugliness and negativity at the audience, leaving you depressed and pessimistic. In Babel bad things happen, but good people make the most of them, leaving an aftertaste of hopefulness and optimism for humanity.
I much prefer that.