Those muscle's get a workout on 3 of the 4 workout days I have, but I only do deads with 60lbs for max reps in 20 mins, so its a cardio workout. I have to say though, it makes walking feel soooooo easy, and general stuff you have to do around the home/at work allot easier also. Its my favorite lift.
I agree. I do Dead's on Friday before back work and it is a real max effort exercise. I stay between 5-7 reps and go as heavy as possible. It has helped me in several areas. I think it all goes back to trying to move as much weight as possible - that is how we grow, so Deads are in my permanent routine.
I find deadlifts are great to keep your posture right; like when your sitting on a chair. Also as jdevlin pointed out they're great for mass. Thats why i think they're essential for any workout plan