Mulgore into the barrens for sure!
My very first character was a tauren hunter untill like lvl 15 or something ( he never made it out of the barrens )
I then rerolled an undead priest so I could heal my friends! Of course my friend played decided on playing a tauren, so I ran all the way to the tauren starting village so we could level together. ( of course this meant I had to run all the way back to UC for my priest trainer ever couple of levels because that was the only place I knew where to find one! )
Darkshore is one of my faves to go through, such a pretty zone.
Plaguelands. That's when you feel just an overall 'dread' for me first in the game. Almost everything that moves was scary and it was so enthralling.
My favorite zone would be hard to pin down, I like so many. The one that I am most nostalgic about is Westfall. It is not the prettiest zone, but it is the one stuck in my memory. It is the first "different" Zone Alliance gets to quest in. The human starter zone & Elwynn Forrest all look the same; like a forest. A lot of time is spent in Westfall & there are some very dangerous mobs, i.e. the Defiance Brotherhood.
Anything but Stonetalon Mountain!
Teldrassil, Darkshore, Ashenvale. Man, those were great zones. Love Duskwood and the plaguelands as well for that creepy ambiance. Least favorites are STV and Desolace.
Loch Modan is the calmest nicest place on Azeroth.
Dun Morogh for sure. I'll never forget how I saw Gates of Ironforge for the first time.
Tirisfal Glades. Walking into Undercity, seeing throne... always brings this one up:
https://www.youtube.com/watch?v=vr7A19TPN_k
STV. I cant wait to start hunting again.
I really had to think about this one, but I'm gonna say Hinterlands. That open air dungeon, avoiding Alliance scum near Aerie Peak, walking down the cliffside switchbacks to get to the Troll fishing village... I also have a lot of music related memories that always conjure images of that zone in my head. Any time I hear Imogen Heap now I am taken back.
Tirisfal Glades. Walking into Undercity, seeing throne... always brings this one up:
https://www.youtube.com/watch?v=vr7A19TPN_k
Especially with all those whispers and bells in background and blood on the floor.
The first zone that came to my mind is Elwynn Forest.
After thinking about it a bit more I would have to say it's actually the 18-35 zones. Specifically Wetlands, Duskwood and the very first few quests in STV (Kurzen etc)
It is not my favorite zone but I am looking forward to questing in Thousand Needles again. I hate what they did to it in Cataclysm.
Teldrassil, my first character back in the day was a night elf. The music and overall look of the night elf zones is so great.
Mulgore. Making my Horde Druid was a massive turning point in my WoW playing career, and has shaped how I have played the game since. I remember running around the bend and down to Bloodhoof Village on Ryder (my Druid) like it was yesterday (it was Jan 2006).
Got my own account early 2005, but played predominantly my Alliance Warrior (Selexin) on a US Server, Kil'Jaeden. I was 17 and I was bad at leveling, especially being a dual-wield Warrior at low levels. Once they launched the Oceanic servers on Jan 26 2006, I rolled Horde and never really looked back. Loved it, loved the friends I made and the community on the server. Fantastic memories. I am desperately looking forward to rolling my Tauren Druid on classic WoW, and running around that bend and down to Bloodhoof Village all over again!
I'd say Ashenvale. Why? Because it was the first zone that got me sweaty hands and sending me chills down the spine only by entering it. The general peaceful & mystic atmosphere paired with the fact that you will - for the very first time - encounter players from the opposing fraction, not knowing if your first fight will turn out in your favour, is truly unique and I personaly havn't found such a feeling in any other game yet.
Really excited for old cities. Looking forward to see Orgrimmar back in its prime days again!
Tanaris. I love that horrendous desert.
I like searing gorge.
Some people disagree but I enjoy it... some of the quests are a bit difficult although easily doable as a group, and it's connected to BRD annnnnd Molten Core so you have to watch for raids.