Warcraft The Shattering
I am really liking the new stuff. The Redone areas, the in game banter between the NPC, the new quests. Everything about it so far is just driving you headlong to the upcoming Cataclysm.
Not sure which Quest lines I liked best. Either the Redridge ones or the Plaguelands. They really are story/lore driven.
oh and with the pre Clysm sale you can get BC and lich for 5 and 10 bucks