The only expansion to EQ that was done right, and was well worth its money. It offered a new race and a nice new continent. At the point of the Kunark release EQ didn;t have to revitilize itself with new gameplay... just had to add more content to an already crowded game. Subsequent xpansion packs to EQ (Velious and Luclin) failed to meet new gameplay enhancements that EQ sorely needs now. As of now, EQ is a game for the addicts. Newcomers are hard to come by.
Still if you wanted to get into the Verant world, all you really need is EQ and Kunark... the rest is really just fluff. Sorta like The Sims only really needing The Sims and Hot Date...