I watched Sin Nombre last week. Really enjoyed it. It's about a family who are trying to smuggle their way into USA from Honduras (through Mexico) and a Mexican gang, some of which attempt a robbery on the train that containing said smugglers. The lead male in the film then kills his gang leader and falls for the one of the smugglers and attempts to help her get to America.
Nobody has mentioned 9 Queens yet. It arrived today from Amazon. Comes highly recommended. It apparently blows City of God out of the water. Although i don't think that's possible. Silly talk!