first things first... dont go with FoTM, you will be greatly disappointing as soon as you are nailed in the face with the Legendary Blizzard Nerf Bat. I would suggest going with a class you want to go with. Each class has good and bad qualities. Due to a imbalance, there are some classes that are OP *ATM* but will not be for too much longer, so that is why I would not go with the "strongest class"
If you want a strong class, break them down by type for DPS:
Casters/Ranged
Mage > SPriest/Lock/Hunter > Boomchicken > Shaman
Melee
Warrior........................> Dk > Paladin > Monk......................................> Rogue
Healing
Shaman > RDruid > Paladin > Monk > .........................................Disc/Holy Priest
Many changes regarding balance are coming in 5.2 which is only a few months away, from what is being eluded, it will likely be 4 months after the release of 5.1.