Jesus, you guys make me feel REALLY old.

Here, let me frighten the hell out of you all.

YEAR OF BIRTH: 1973

FIRST GAME: Space Invaders

CHILDHOOD DEFINING GAME: Pac-Man and Dragon's Lair

ADOLESCENCE DEFINING GAME: Talisman

CURRENT FAVORITE GAME: Mortal Kombat (2011) and Elder Sign: Omens

-1975
-1980 - got my Odyssey and Atari 2600 w/Combat
-Childhood: Yar's Revenge
-Adolescence: Street Fighter 2
-Current: Alice - Madness Returns

The create a character mode is what has me.

Birth: 1990

First Game: Super Mario

Childhood Game: MK3

Adolescence: Rampage: World Tour

Current Game: Sly Cooper HD collection

Birth: 1993

First Game: WWF Attitude

Childhood: Banjo-Kazooie

Adolescence: Super Smash Bros. Melee

Current: Mortal Kombat 9

Born: 1993

First Game: Ultimate Mortal Kombat 3

Childhood Definer: Super Mario World

Teenage Years: Super Smash Bros Melee

Currently Playing: Monster Hunter Tri

Favorite All Time: Super Smash Bros. Melee

Yes, Fatal Frame has been eating my life away.

Ok, the first time I did this, I was thinking off the top of my head. Now, I have thought this through.

---------- Year of birth: 1996
First game: X-men (Fighting game) / X-men vs. Street Fighter / Street Fighter EX plus Alpha / Mortal Kombat / MK:Trilogy

(I seriously don't know which one of these I played first.)

Childhood defining games: Duke Nukem 3D (PC) / Nightmare Ned (PC)

Adolescence defining games: Mortal Kombat (2011) / Heavy Rain (PS3 exclusive game)

Current favorite game: Mortal Kombat (2011)
----------

I don't have my old Nightmare Ned disc, 'cause it was shattered by my old PC, but I did get a new copy around a year ago. I also don't have Duke Nukem 3D anymore, but around a year ago (again), I got Duke Nukem: Total Meltdown, which is a Playstation port of DN:3D.

I would've put Quake in childhood-defining, too, but I figured two was enough.

DOB:1988

First Game: Pac Man on Atari 2600

Childhood Defining Game: Street Fighter Turbo II on SNES

Adolescent Defining Game: Mortal Kombat Deception on Playstation 3

Current Favorite Game: The Elder Scrolls IV: Oblivion on Playstation 3

I ended up changing my answer under "Adolescence Defining Game", simply because the new answer is far more accurate. I had a really hard time trying to think of a video game that was defining for me in that era, simply because I had backed off of video games and was playing fantasy/sci-fi board games at that point. I really didn't get back into video games hardcore until I went to college.