when i wanna kill my back i do. . .
1) five sets of wide-grip pull-ups, 10 to 15 reps per set
2) 3 or 4 sets of dumbell rows, 6 to 10 reps per set, starting with a 130 lber and working up to a 150 lber
3) 3 or 4 sets of backward cable crossovers (i.e. for the back instead of the front), 12 to 15 reps per set
i have other things that i throw in from time-to-time. . .barbell rows, dumbell flyes, pull downs, close-grip v-bar pull-ups, etc. . .but i generally try to stick to 10 to 12 sets total.