For me, so down shoot me down, i think a pally will be best. The reason is that there are only 4 things that i have to cast. I haven't played my pally in awhile so i forgot what the spells are called, 1st throw my shield, cast my shield block (i keep that up the whole fight), cast my ground aoe, and use my hammer (i use this when cd is done). So that is really only 2 things that i have to do during the fight is keep my shield up and use my hammer. The other 2 are a one time use.

I do play a dk, i am currently spec and geared as dps, but when i was getting to 80 i was trying to get gear for tanking. I have to say that trying to get gear for tanking for a dk is not easy at all. I find that the 540 cap is really hard to get. I also found that green gear had more defense then blue and epics. For instance i had a blue peice of chest that give 65 defense and when i upgraded to the t7 chest i only got like 45 defense. I think that blizzard screwed up on there stats for teir stuff. My dk has gear to tank but i only stand at like 2300 health and barely having 540 defense. The only way i was able to make the cap was i had to use my dragon gems (only jc can make and use) and had to make 3 x 27 defense gems.

I am only dual boxing my priest and dk now. Right now my dk is in one of the top guilds on my server. We have heroic nax on farm so i am working on my dps and tanking gear now. I probably will not 5 box again until 3.1 comes out with dual spec. When 3.1 comes out i should have better tanking gear and try out tanking with my dk. If there isn't a problem then i will use my dk as tank.

Here are the reasons why I (key word I) don't think i will like dk as a tank (again with no experiance tanking as dk). There is a lot more that you have to do during your tanking. The aoe granted is bigger then the pallies but unlike the pallys where you just cast it you actually have to click where you want to cast it. I find that with my dk i have to do a lot of combos to max out my dps and i am thinking that i will have to do the same for tanking... well like i said i will see what happens, going to look to see how you tank.