Well i think a tierlist of all classes based on their player base numbers will be helpfull, because ive havent seen an updated one:

1.Paladin, Dk, Warrior
2. Mage (some people say they aren much played but i think they are top 5 on their player rate), Druid
3. Hunter, Rogue
4. Priest, Shaman, Warlock


PS: If you think something on my ranking isnt as accurate pls post a comment or correct me. Thx for stopping by :D