Too many to list here, and I know I'm leaving off some of my favorites, but here goes (in no particular order):
-The Descent series, for the most pulse-pounding and challenging multiplayer experience ever, as well as introducing me to the amazing world that is the Internet through PlanetDescent (which I happen to now be a staff member of). Long live 6DOF!

-The FreeSpace series, for obvious reasons, and because it has the best singleplayer storyline and best villain of any game I've ever played
-Twisted Metal 2 for PS1, for those times when you just have to blow the **** out of other cars
-Demolition Racer for PS1, for those times when you have to crash the hell out of other cars

-The original Genesis Sonic games (1, 2, and 3; I've never played Sonic and Knuckles), for being the first real video games I ever played. They're still a blast today.
-Super Mario Brothers, just...well...because

-Donkey Kong Country 2, for being the most engaging 2D platformer I've ever played; I could play this for hours on end with no problem.
-Tomba and Tomba 2 for PS1. They were event-based 2D platformer games with 3D graphics. Plus, Tomba had pink hair and fought evil pigs by biting them, which made him one of the coolest heroes ever.

-Pac-Man World for PS1. While I acknowledge the original as one of the kings of games, I enjoyed this 20th anniversary 3D platformer much more.
-The Incredible Machine 3.0 for the PC. I started playing this game almost 10 years ago, and there are still a few puzzles I've never been able to figure out. (I've honestly never looked for a hint site after all these years; I still hope to figure out all of them on my own.

) The redbook soundtrack was also awesome, with everything from hip-hop to techno to hayseed.
-The Myst series, for being the most beautiful games I've ever played, as well as the most challenging. I can't say that I didn't look at hints for these games, though. Myst 4 was the most engrossing gaming experience I've ever had; it truly felt like I was in another world.
-Starship Titanic for the PC, an adventure game that introduced me to Douglas Adams's zany brand of humor. It featured robots that you could actually talk to by typing in phrases; this may sound cheesy, but they had over 10,000 lines and
16 hours of dialogue to throw back at you. An incredibly fun, and funny, game.

-Age of Mythology, the only RTS I've played so far (nope, I've never tried Starcraft and Warcraft, before you crucify me) that I've really enjoyed. The storyline was great, as was the voiceacting, and the graphics were simply beautiful.
-The Ratchet and Clank series for PS2. Although I felt that some parts dragged out for too long (gathering bolts for massive weapons), I have to respect any game whose stated purpose is to "blow **** up"

-Microsoft's Solitaire, Minesweeper, and Spider Solitaire, for giving me countless hours of frustration and making me want to smash my PC to bits

-The Legend of Zelda series (specifically Oracle of Ages, Oracle of Seasons, Ocarina of Time, and Majora's Mask), a truly timeless gaming icon. I only beat Ocarina of Time earlier this year (it was the first time I ever had an N64), and I'm actually still working on Majora's Mask, but I love both of the games, as I did the two Game Boy Color offerings.
-Super Smash Bros. Melee, for giving me countless hours of entertainment at college. I'm buying a Gamecube just for this game alone (the other great games on the system are just a bonus), and I'd consider it to be worth every penny.
I think that's it, but I'm sure a few have slipped my mind. I can never be accused of liking the newest and most popular games, but I can be accused of holding dearly onto older games that didn't sell too well, just because they've brought me so much joy.
