It's an opinion of mine that there is a moment in each of your favorite games that are burned into your mind, and you will never EVER forget. I don't know if that holds true for you, but it certainly does for me. I would be very interested in knowing your favorite games, and what those moments are, if they exist. I would assume that this will become a spoiler filled topic, but my own posts will be spoiler free where possible. If not, please use the <spoiler> tag.
1) Zelda: Wind Waker. This game had two scenes of very high note, and I would be remiss if I didn't mention one of them, so I must mention both. The most obvious scene was the ending. The contrast of the most dark story in a Zelda game, and the light artstyle had really had a profound effect on me throughout the game, and with the ending, everything was brought together in a way that I had never foreseen. The other scene, I will describe with a track title from the Chrono Trigger OST. "The Day the World Revived"
2) Xenogears. The moment would have to be the first scene in the second disc. It was at that moment that I had decided that Xenogears had earned the trophy for being the best game I had ever played, and everything after was just a formality. It wasn't really a shocking or unpredicted scene, but it made me smile, and it was some really great imagery.
3) Chrono Trigger. "The sea of clouds has parted and the storm has finally abated. Could the long winter finally be over?" The scene which I refer to of course is the part of the game which caused this event. It was incredibly shocking to me that a video game could do such a thing at the time.
4) Metal Gear Solid. "Why? I loved you..." I am sure that everyone who has played the game will remember that moment forever. The character which I am referring to has to be the most dynamic ever in the history of a video game. It shouldn't have surprised me by that point in the game, as it was the last scene before the second disc, and there were several before then that had a great deal of impact ("Compared to you... I'm not so bad."), but that scene is truly one which can never be forgotten.
5) Eternal Darkness. "Charlemagne...." The character of the third chapter was special. There were events going on in the chapter which really brought the game to life. Although later chapters would improve upon the formula greatly, and some of them hit very close to home, I have found that I still like the 3rd chapter the best. By the end of the chapter, you know very well what is going to happen, and you can't do a thing to stop it. You just try to do your job. I must also give a small mention of "The Gift of Forever" though.
6) Final Fantasy VI. This was a game that was broken into two parts. The first part ended with a fairly traumatic event, and I think it goes without saying that this was the moment that most people will remember of this game the most. "On that day, the world changed forever." I really became quite the Square fanboy when this game came out, and it really took Final Fantasy IX, Chrono Cross, and Legend of Mana to really make me come to realize how horrible they had really gotten.
7) Final Fantasy IV. I really think that this game was out to set the record of most deaths in a game when they made it. But regardless, it really seemed to work. It was one of the first games to really try to have a story that stood head and shoulders above the rest, and I really respect that. I really think that the moment that stood out in this game for me was Palom and Porom. It was a simple scene, but was quite effective in its job.

Conker's Bad Fur Day. Everyone no doubt remembers the "Saving Private Ryan" stuff that was in all the trailers. I choose more to remember the ending above all. The game was often over the top, and was NEVER serious. That contrast to the ending was a real shock, and will forever be remembered as the last of the Rare greats, and my favorite game from Rare. I think that it was a good way to remember my old friend Rare.
9) Silent Hill 2. Angela. Knife. Empty room with big mirror. I had a screenshot of that part of the game as my desktop background for many months. Whenever my roommate saw it, she knew instantly the meaning behind it, even though she had never played the game, and had no idea who Angela was. She said it was a nice background, but WAY too morbid. Given that it was Christmastime though... I needed it. But the fact of the matter is that that scene is my most memorable. But the line that I remember most from the game... "James... you meant so much to me" will never leave me until the day I die.
10) America's Army. I actually really have a problem with putting this game on my top 10 list, beating out other games I love very much. It's a PC Game, and it's an FPS. Both of those things I generally dislike. However, it deserves it's place here. The first time I played the game online, I was playing on The Bridge map. I looked down on the bridge from above, and it was exactly what I had wanted to see. The friendly side was wearing pure white arctic combats, and were climbing around on the bridge. There was a dense ice fog in the level, and both sides were taking heavy casualties. There was shooting, explosions, bleeding, and dying. It felt like home to me, and I loved the map very much. It's just the general atmosphere I love so much. I am a Canadian. I like snow.
Honorable mentions would include reading the "diary" of the main character in Secret of Mana in my Nintendo Power magazines, hearing the radio announcer in SSX 3 talk about Dangerous Dave, seeing the main gates of Valua open up in Skies of Arcadia, and fighting my first no-win scenario in Wing Commander III.