After taking WHM to 60 a year ago, I began playing a little more defensively as a tank.

Make the healers life easier, and everyone's life is easier. Lose a few hundred dps, gain more since the healer can dps. And/or I'm not dead.

I'll still stance dance on fights I'm comfortable with, and especially if the healer has good gear and is skilled. But I learned how much of a pain in the ass it is to heal a tank that stays in dps stance all the time.