Personally I prefer story points per card, and then calculating the average velocity of the team per sprint vs. the number of story points left in the backlog.

Personally I prefer story points per card, and then calculating the average velocity of the team per sprint vs. the number of story points left in the backlog. This presumes a deadline more than a sprint away, though, since it's a little fuzzier. Mostly it keeps people away from saying "Hey, we said this card would only take X hours!"