Hey, can I reply to this? I'm in here reading because I've been raiding with my SPriest a lot lately, but as a pally healer my hierarchy is DK, Pally, Warrior, Bear. I will say that my experience with the Bear tank may not be valid, as our Bear tank is not as well geared as the rest.
I have learned to love healing DKs because they just don't die. The sh't has hit the fan a couple of times and I've gotten that bad feeling in the pit of my stomach - you know the one, when you're waiting for your heal to land and are sure it will be milliseconds late? - and surprise, the DK survives until my heal hits. And our guild has had to sit through sometimes a full minute of our DK tank soloing the boss after the rest of us wiped because he refuses to just stand there and get killed. "Hey, I'm trying to die, it's not my fault he hits like a wuss!" And one night I apologized to the DK tank for forcing him to blow his cool-downs, and he said "no problem, they're all real short, the longest is five minutes."
Pallies next because of the linear damage as another poster said, Bear tank last because I have the complete opposite experience with her from the DK tank, and that leaves spot number 3 for warriors.
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"the people can always be brought to the bidding of the leaders. That is easy. All you have to do is tell them they are being attacked and denounce the pacifists for lack of patriotism and exposing the country to danger. It works the same way in any country."
Hermann Goering, April 1946.