Horde, I think I'm going to do a melee group first and a ranged group second followed by a farming group after that if I'm not burnt out yet (farming group would likely be 4 mages or warlocks and a healer or something).

Group 1:
Warrior
Paladin
Druid
Shaman
Rogue

Group 2:
Warrior
Hunter
Mage
Warlock
Priest

The reason there is a warrior in both groups is because there are only 10 classes so I have to double-up somewhere (I want one of each class to 70). I picked warrior as the class to double up because having a tank makes every encounter far easier and warriors are still the best tanks in my opinion. Group 1 will be harder to micromanage because all characters are melee but group 2 will be harder to macro manage because there is only one true tank and one true healer. In group 1 if someone pulls aggro they will be fine while group 2 is full of glass cannons with no threat reduction and a single tank.