Then there's EverQuest II's The Shadow Odyssey, EverQuest's Seeds of Destruction, and Asheron's Call's just-released 100th update. If you've got long-inactive accounts with any of these games, the devs are trying to win you back! If you're still there, they're trying to keep you from leaving for Warhammer Online or from freeing yourself from the genre completely.
Are any of these expansions going to do the job for you? And if so, which ones?