As a Halo fan, I often reference or see references to that first moment you stepped out of the drop ship on the second mission and saw the world around you open up. Part of it was the time, and part of it was the juxtaposition of the first mission being a narrow hallway crawl, which then opens up into the vista we see. It's an incredible moment, one of those gaming memories I'll never forget.
Skyrim gave me about a dozen such unforgettable gaming moments. Too many to list in any detail, but a few:
My first would be my first horseback ride across Skyrim, from Solitude to Riften, discovering the breadth and detail of the land along the way. The tundra, the lights in the sky, a snowstorm in the mountains, the glory of the autumn forests near Riften at dawn. I remember stopping and looking at the fish leaping up a small waterfall, which ran under the bridge I was on. And I don't think I'd ever been so excited to settle in and explore a word at length. My subsequent time with the game did not disappoint.
Discovering Arcwind Point for the first time. It's a stunningly designed area, but the battle that broke out between a frost dragon, the Draugr and myself was one for the ages. Up and down the ravine, bodies fus-roh-dah'ed off ledges, the dragon going nuts on everyone, then ending with a three way fight between myself, a high level Draugr Deathlord and the dragon. Just a truly epic game space and a sprawling battle. The snowstorm we were in was the icing on top.
The conclusion of the events in Frostflow Lighthouse. Picking up the pieces of what happened to this couple that planned out the twilight years of their life, and what befell them in Skyrim's cruel land. Their troubled but loving relationship with their kids. The tragedy of it all. And then, realizing what I needed to do at the end. No in-game prompt, no big waypoint telegraphing it. Just a final moment of kindness prompted by the story. And the game recognized it. It was a hugely powerful moment for me, one that really highlights the power of interactive story telling. Of the three Bethesda games I've played (Oblivion, Fallout 3, Skyrim), it's probably my favorite story moment. Or at least the one that moved me the most.
A battle outside of a fort way up in the north. I'd learned Frenzy and was working on using it alongside my archery. I tagged one Stormcloak in the fort, and he chased me outside the entrance. He then got into it with someone else there, so I tagged both of them. And then, the rest of the Stormcloaks came running - 8-10 in total. And I hit them all with Frenzy, and the place just went nuts, everyone fighting each other. I stood off to the side, and managed the fight to even it out. Also, there were a couple horses in the mix. It was one of the most hilarious things I'd ever seen, and was just crazy fun. At the end there was this big pile of dead guys (and horses) and I barely had to lift a finger. And it really opened my eyes up to the array of possible ways to play the game, and what a big sandbox Skyrim really was.
There are many more. But those are a decent sample. Skyrim's been good to me. My favorite game this console generation, and high on my favorite games ever. A year and change later, and I still look forward to playing most nights.