Do you need an expansion packs for World of Warcraft

While you CAN play World of Warcraft with out either of the current expansion packs, you will not have access to levels 61-80, wont be able to use the professions past a certain point, and will not be able to visit Outlands or Northrend. It would be better to just go a head and purchase the expansions now so you have access to all WoW has to offer.