Elysium is set in a world with an over-populated, dirt-poor Earth and a wealthy, beautiful, wonderful and extremely large free-space settlement in Low Earth Orbit called, you guessed it, Elysium. The movie answers one of the great questions of space settlement: why would anyone want to live in space? Because it can be a really great place to live. There's another important pro-space settlement message but I don't want to spoil anything, so I won't tell you what it is.
Some in the space movement have criticized Elysium because, among other things, it is a haves vs. have nots movie and they don't like such things. To me, that's like complaining that dogs bark. It's a movie, and this is one of the standard stories of the entertainment business (going back, at least, to Cinderella). Other's complain about technical inaccuracies, of which there are plenty. To which I say, it's a movie, folks, not an engineering project!
So if you want to see a beautiful depiction of exactly how great living in space could be, and have a good two hours of entertainment to boot, go see Elysium!