To those who responded to me, marking is really only beneficial pre-lvl 50 content, I agree. There isnt much i mark in raids groups, but I will still mark Haukke/Copperbell HM, AK, Pharos. If you dont need to Mark in order to take aggro early on, great for you.

But, remember that you are making an example for newer players. Not every tank (most tanks even) are good tanks that know how to maintain all aggro without marking, and if your "new to the game" DPS is hitting whatever they want to hit, they are being taught wrong, and will potentially screw things up for future party members. As a leader (which a tank is), it is preferred you Mark. can only make things easier. if you dont have the room to mark, theres a good 1 button macro for that I can share.