The feeling I got arriving in Northrend, exploring the Howling Fjord for the first time. Northrend in general is awesome imo
Mani - Kanrethad - Manione
Twisting Nether EU
Dread Wastes I love the dark looking zones, devastation, sha ectoplasm everywhere, i love it.
in classic WoW i had many favorite zones such as Feralas, Arathi Highlands, Hillsbrad Foothills, Alterac Mountains. In general i liked Lordaeron zones the most because of scenery and lore/background.
TBC Nagrand and Shadowmoon valley
Wotlk Howling Fjord hands down with Grizzly Hills coming at second place.
Cata Uldum left a strong impression even tho it was a bit crazy on the lore side.
Probably pre-Cata EPL/WPL. Icecrown.
I love Paladin lore.