Super Nintendo:
Gyruss - Really the first game my sister and I ever played together.
Bubble Bobble - Again, another bro-sis bonding experience.
Simon's Quest - First Castlevania title I ever played. I find myself humming the music sometimes.

Gameboy/Color/Advance/DS/DSi:
Pokemon (series) - I've put more hours into Pokemon than I have any other series. Simple, but deep.
Castlevania (series) - The only platformer I've ever enjoyed on any handheld. Again, music humming.
Medabots - A fighter-type game with customizable robots. Frustrating, but a hell of a lot of fun.

Xbox/360:
Halo (series) - If anything ever came even halfway close to topping Pokemon, Halo was it.
Modern Warfare (series) - I'd always thought I'd be a Halo fanboy, but IW showed me there's room in my heart for two titles.
Mass Effect - Barring elevators, I loved every minute of this game. Eleven play-throughs so far.
Gears of War (series) - Best voice acting ever.
Oblivion (series) - My first 360 title. My dark-furred kitty of doom looked damn good in Daedric gear.
Rainbow Six Vegas (series) - Attack and Defend matches on Calypso. Hilarious, fun, and intense.
Call of Duty: World At War - I don't care to admit it, but this game was surprisingly fun, if a little watered down from the Modern Warfare experience.
Left 4 Dead - I've never laughed so hard at the idea of someone being pulled out a second story window by an undead creature's super-elongated tongue.
Prototype - Now that's how you do a super-human video game.
Star Wars: Republic Commando - Principles of teamwork and clone/Mandalorian identity influenced how I've managed my gaming team over the years.

PlayStation/2/3:
Spyro (series) - My pick for favorite console platformer and the first game I owned for the PS1.
Crash Bandicoot - Hour-long sessions with friends and I trying to beat all the time-trial scores.
Tony Hawk's Pro Skater - The first, the best. The one before I lost respect for the Hawk name.
Killzone (series) - I mostly mean KZ2, but the first game did some pretty neat things, and I liked Colonel Hahka (Hakha? Hakawkaw?)


***Warning: Other games may contain massive amounts of win. Because they aren't on this list, they either a) have yet to be added, b) have yet to be released, or c) contain massive amounts of win as per your own personal opinion. Disputation if any of the aforementioned games on an irrational level ("That game sucks dick"-style sentiments) will be disregarded as juvenile hormonal outrage.