Games that were some of my favorites throughout the years, in no particular order:
Ultima V on the PC. It was the first Ultima game I played and just really like it. I liked these older rpgs because you couldn't just click your way to the end like some modern rpgs.
Elder Scrolls III on PC. I liked how open ended it was. I actually played Oblivion much more than this one, but I still like this one better. Sadly, I just don't have the time and energy anymore to really get into a game that is so open ended.
Zelda Ocarina of Time on N64. Seeing a zelda game in a 3d environment for the first time was cool. Just a great game. I still play it sometimes.
Tony Hawk Pro Skater 3 for PS2. It was the first Tony Hawk game, of many, that I played.
Skate for XBox 360. I was getting tired of the tony hawk games and I liked the innovative controls for the game. I still play this one a lot. Ironically, I was never a skater. I think I was only on a real skateboard once or twice in my life.