It was during Morrowind when I kept running from Balmora to Caldera at the beginning of the game. I thought that it would be great if I could take a short cut over this mountain instead of running around the base of it. I was completely blown away when I made it to the top and saw the back wall of Balmora down below me. I couldn't get over it.

I was also remembering the first time an NPC said, "Ok going home now" and I followed them nearly all the way across the map. I don't know what I expected.... I guess I just expected them to disappear. But again, it really blew me away how Beth could make such a 'thorough' game.

Do you remember the first time TES blew your mind?

Morrowind, of course! The first time I walked from Balmora to Pelagiad. The way the scenery changed and became so beautiful with the flora. Of course, today's graphics and all are so much better, but still, that was impressive back then. I miss the "newness" of it all.

Morrowind, character customization and class picking.
I was young.

My first ash storm and first visit to Ald-Ruhn. I came out of the Mages Guild right into the storm in full swing. I'd heard you could catch diseases from Blight Storms (which is what I thought it was) so hid in the doorway of the guild. Gradually, I was able to make out the Fighters Guild across the street so I tried to get there as it looked more sheltered. In between the buildings, I lost sight of both of them and had to inch my way,leaving a trail of dropped items behind me so I could tell my progress.

The howling wind, the dust flying, it was truly terrifying.

They're going to move this to TES general discussion. They've done it with all my threads, even the ones that do talk about Skyrim. :\

But for me, would be when I picked up a random item in Arille's tradehouse, and the guards came. That was a concept I had never seen before in games.

Yes when i was playing Oblivion i got out of the prison and i just saw chorrol and then while i was crossing the bridge connecting to the entry of Imperial City i just saw Bruma and i was like OMG that is so AWSOME if Oblivion had Skyrim alot of things like smithing cooking and all that it would be the best game i′ve ever had played!

My first TES was Oblivion, I wasn't entirely blown away but surprised on a few things
(my lack of emotion makes my "surprised" somewhat equal to your people's "blown away")

1st thing that amazed me was that you could take anything off of dead NPC's that they had, wear their clothes and everything. Never played a game before where each NPC had as much depth as you considering your both put under the same format.

2nd thing was every single Object was able to be taken or moved, in previous games, the shown objects were untouchable glued things to a table or just a Book case with books that meant nothing and were glued there with no purpose.
While I found that every single book on the book case could be read and they weren't all the same book either

3rd was the very first thing I decided to do, which was climb the first mountain I saw. In addition, After doing that I could still see Imperial City from the distance thinking I wouldn't be able to see anything in the distance, just fog or something on how most games put it if there's a long distance to travel in 1 cell.

I had forgotten the ash storms--it did make you feel like you were in them. In Daggerfall, when I first realized the seasons changed, I was blown away.

My first experience with picking up a "clutter item", I thought it had to be quest-related, then realized that EVERYTHING was able to be picked up.

My first experience with Levitation in Morrowind opened up a whole new "vertical dimension", and I quickly realized just how much of the game was actually written to take that into account.

Rounding a bend on the winding road to Bruma, I spotted the Imperial City far below, and the view simply left me standing there in awe.

Each game gets so much better in some ways, and gives up so much in others, it's both exhilerating and frustrating.

When you first walk into the shivering isles, you know, when the wall turns into butterflies.

The first time I got lost in Vivec. I'd used a scroll of Almsivi intervention to avoid getting mauled and ended up spending hours lost and confused roaming the corridors of Vivec. I've never played a game with a city like that.

It wouldn't happen to be that spear that is leaning against the wall that you picked up, would it? The first time I went into Arrille's I tried to "buy" that spear by activiating it. Big mistake! The violence that erupted all around me is still one of my most vivid Morrowind memories.

I remember in Oblivion (my first RPG ever) exiting the jail and deciding to break into someones house... I was amazed that I had as much freedom to kill people and steal stuff as I did.

the silt strider doing his howl thing while getting off the boat in seyda neen

Getting out of the character creation area in Morrowind and having total freedom as to where I went, what I did, or who I talked to.

Oblivion - walking to Chorral from the Imperial City.

Shivering Isles - butterfly door.

Skyrim - the rugged beauty of the Reach

The first time i was really impressed with TES was the ragdoll physics in Oblivion. It really blew my mind. Being an archer got THAT much better!

My jaw dropped. That was SO COOL and unexpected.

That reminds me of another moment. I was in Vivec and it was raining (remember the raaaain every daaaay), and I was looking at the banners that hung from the bridges as they swayed in the wind and I noticed for the first time that the clouds were moving; and then I looked down at the water and saw the raindrops hitting the water............ and there was this beautiful music playing and I just tripped on it for awhile... It was beautiful and so real....

I had never played an open-world game before Oblivion, and I was amazed at first by the physics engine. Getting out of the sewers, I figured I would just end up in a city like in the linear D&D-based RPGs. But instead, I saw a gigantic world in front of me, all so interactive as even the most useless junk in the dungeon had been.

I really felt like I was in another world, not just playing a game. In many ways, Skyrim has lasted in this way much longer for me than Oblivion had. The graphics convey such a solid world that still feels so neat and beautiful to me.

When stupid child me finally figured out how to leave the sewers in Oblivion and got a definition of a "sandbox game."

Basically first moment out of the sewers. I mean I'd never seen an open world game before, and come on, that was just amazing.

I was first blown away by the fact that Morrowind had canes that looked exactly like the ones Sly Cooper from the Sly Cooper series uses. It was awesome.

It never blew my mind, first Bethesda game I played was Fallout 3 and neither Skyrim, Morrowind nor Oblivion has been able to beat it.

Morrowind, the second i stepped out of the census office and the game tip said : your on your own now, i felt so alone and small, i felt like i was part of the world, ill never forget that.

When I entered the city of Daggerfall for the first time (which also happened to be the first town I visited in the game), and I was amazed at how large the city was and how alive the game world seemed to be with all the NPCs and so on.

In contrast, Morrowind was a disappointment in this regard as I didn't find the game to be much alive. All NPCs just stood at the same spot 24/7.