As far as I can tell there is no real reason for me to buy BC before my main hits 60. I don't find either new race very compelling and if I understand correctly even if I get the expansion my existing characters can't access the new lands until they hit sixty. So unless the new profession and items it creates are only available to BC owners there's no rush. Am I wrong?
Well if you had an itch to do jewel crafting then that may be a reason but if you don't want to visit either of the two newbie zone areas and are not level 60 than nope.
How about if you want to experience the quests in the zones of the Blood Elves and the Draeni? I don't know if multi city quests exist but if they do it was my understanding that you needed the burning crusade to access them.
Born too late to explore the new world. Born too early to explore the universe. Born just in time to see liberty die.