My programming is a bit different these days, but in the past on top of deadlifts, etc I'd be doing rows once a week on a three week cycle, working up to a heavy double one week, doing ten sets of one or two with little rest another, and then a 3x5 the third. For accessory work, I'd do Kroc rows once a week, or regular dumbbell rows, and I'd do body rows or pull-up work as well. Prior to this, I was doing Olympic lifting with no specific back work other than trying to keep it tight during training.
My back definitely has gotten stronger over the course of my training, I just seem to have trouble doing maximal effort work with it when I try to train it directly. I don't know if I'm not using the muscles properly or what when I do the exercises.