I used to drive with the tank for PVE but have switched to healer instead. I feel it allows better movement for ranged dps when the aoe damage comes in.

I only switched after experimenting with a 4 dk plus 1 priest team a while ago and found it better than leading with a tank....felt more like a hunter and a pet arrangement with the dks being pets. Anyway, I've changed all my teams to be lead by healers now.