Fallout 3 on the 360. I got caught up in the marketing for that game for years prior to the release. I had only been exposed to console games up to that time and had a long romance with Oblivion.
I wouldn't play through Fallout 3 again but when it came out I had a blast. It was definitely a moment where my super high expectations met with what seemed like high quality delivery.
It definitely influenced my thinking on gaming and it got me interested in computers for the first time since I was a kid.
I first saw Oblivion at a friends house and I quickly bought it for my budget PC. It farted out a potato version with transparent grass, no fog, brutalist looking structures. It was just very simple, no details or anything but I loved it. I lusted after an Xbox 360 because gaming PC's were prohibitively expensive. I got it, and my pc dreams were lost. I loved Oblivion, loved xbox live, became an Xbox fan, monthly fees, CoD, GoW, etc.
Then I heard about Fallout 3.
I became interested in the Fallout franchise and the advertising and Todd Howard's marketing prowess bit me hard. I got obsessed, and managed to download and play Fallout 1 and 2, which made me interested in PC gaming. They were small games and old enough that my old PC could handle them fine. I had a blast. I also found out about forums and how technical information is shared, I saw command line instructions for the first time, the altruism in information sharing on the internet and more.
I had been an Apple convert and when I tried to get Fallout to work on their platforms I experienced problems because of Apples forced obsolescence, functional design and lack of gaming platforms. Steam hadn't come to Apple yet. I managed to get them to play through apple OS though. That challenge inspired me to have a deeper curiousity about computers and programming. I am changing careers, attempting to break into tech and entertainment by learning Unity and developing my own games, and I am still looking to get that ultimate gaming pc.
So yeah, I definitely I got caught up in the Fallout 3 thing at the right time.