For back, I mainly stick with pull-ups, heavy barbell rows and deadlifts. Occasionally I'll switch it up and do cable rows or T-bar rows, still going heavy. For pull-ups I usually shoot for a certain number (say 50) and do as many sets until I reach 50. If I'm having a low energy day and I get to the point where I can only do a few at a time, I'll cut down my rest time to like 10-15 seconds at the most and just crank them out. Keep in mind that this is all the way up, all the way down. I'm exercising to train muscles, not just shooting for a number.
For back, full range of motion is very, very important. Especially for pulldown motions, such as pull-ups or using the lat pulldown machine. Also, I always stretch a little after any pulldown motion exercise and flex between rowing exercises or deadlifts, such as doing a double biceps pose or a front lat spread. I have no intention of competing, so "posing" for me is basically just flexing targeted muscle groups... Yeah!
I do think it's okay to cheat a little on the really heavy sets, such as the last set or two.
Basically, master the form on your back exercises, shoot for full range of motion and go as heavy as you can (6-8 rep range mostly, but do some power sets of 4 reps or even lower sometimes). Deadlifts allow you to handle a lot of weight, so make use of that. I usually do a warm-up set or two for deads and then load on the weight so I'm failing after 5 reps, 3 reps, then maybe 1-2 reps.
Stretch a lot after you're done working the back. I like to hang from a pullup bar with my grip as wide as I can and really stretch out my lats. Then I'll go over to a treadmill and bend into it (or anything you can grab onto and lean into it, such as doorway or whatever), stretching even more.
Remember, the back is pretty complex. You want to know what the muscles were designed for (essentially pulling the shoulders back and down - pulldown, and then rowing motions). You want to work the pulldown function as well as the rowing motion.
Master form, full range of motion, go heavy, stretch... Bingo!