What's your favorite high level zone, from any expansion, not a raid. Examples include Eastern Plaguelands, Netherstorm, Shadowmoon Valley, Storm Peaks, Icecrown, Twilight Highlands, Dread Wastes, and Vail of Eternal Blossems. (I'm sure I'm missing several from Vanilla, just has been so long, I forgot what the original high level zones were).
Personally I'm partial to Storm Peaks. I loved the titan lore, and the zone was just gorgeous to me.