What cl should i be in wow?

Hi, i have just come back to wow and i am not sure which cl to level to 85 first. i like dps most as a role but havent really tried the other two. i also like pvp more for end game but love pve too. i have a level 79 mage, 75 warlock, 70 shaman and 48 druid, it doesnt matter what lvl they are i just want one that i wont get bored with like i have been doing with some of the cles. or should i lvl another cl from the start?also which spec should i choose? I would appreciate all ur help. Many Thanks