NES - Mario 3, nothing finer than this.
SNES - Yoshi's Island
N64 - Super Smash Brothers, i probably put the most time in this game than any other game ever. Probably around 500 hours with friends.
PS2 - GTA3, at least 100 hours in this. Still my fav GTA ever, can't wait for the remixed PSP version.
NES - super mario 3
C64 (i dont think this counts) - last v8 / thing on a spring / impossible mission
GB - tetris/kwirk (yes, kwirk)
SNES - super mario kart
N64 - missed the n64 actually but PSX - wipeout 3
GC - super monkey ball 2/mario kart/prime
NES Tecmo Super Bowl
SNES Donkey Kong Country
Genesis Sonic the Hedgehog
Saturn Skies of Arcadia
N64 Conker
PSX FFVII
PSII Kingdom Hearts
XBox KotOR
GC Resident Evil 4 (can't stop playing)
8 bitters: Enduro (atari 2600) or Super Mario Bros 3 (Nes)
16 bitters: Super Mario Karts
32-64 bitters: Doom (PC, PS1) or Grand Turismo 2 (PS1)
Present gen: TOCA2 (PS2) or GTASA (PS2)
NES: Too many to think about
MS: Phantasy Star
Genesis: Tie between PS2 and every sports game
SNES: Super Metroid (Honorable mention to Chrono, FF3, and SMK)
N64: Mario64
PSX: Xenogears
DC: NBA2k2
PS2: Winning Eleven
Cube: Wind Waker
I don't have a Xbox, but I have played a lot of Halo and Madden on my friend's Xbox. Good party system. Too bad the controller is ass for WE.
Edit: For Atari I don't really remember which game I played the most. I played all of them so damn much back then.
SMS: Wonderboy in Monsterland
SMD: Road Rash
PSX: Tony Hawk's Pro Skater 2
PS2: Grand Theft Auto 3
Xbox: *Soon to be Forza Motorsports *
Cube: Donkey Konga
N64: Mario 64
GB/GBC: Pokemon Red/Yellow/Blue
DS: ----
PSP: ---
oh:
PC: Counterstrike
Havent gotten a DS or PSP yet, but i intend on them soon. Australia is a bit expensive for PSP, so it may not happen.
8 bit: Mario Bros
16 bit: Street Fighter II
32/64 bit: KOF 98, SFA3, or Goldeneye
Dreamcast (transition generation!): probably MotW, NFL2k1, or SFA3 again...
This gen: FFXI, SFIII or VF4
Atari 2600: Video Pinball
Odyssey 2 (my friend's): KC Munchkin
Intellivision (also my friend's): Baseball
Colecovision: Venture
Apple IIe: Castle Wolfenstein or Ultima III
NES: Contra
SNES: Super Mario Kart
Genesis: Flashback
3DO: Star Control II or The Incredible Machine
PSX: Twisted Metal 2
Saturn: Saturn Bomberman or Clockwork Knight
N64: Mario 64
Dreamcast: Virtua Tennis
PS2: GTA series
Xbox: I play the shit out of the Xbox but I can't think of any game played more than others
Gamecube: Super Monkey Ball 1/2
Didn't get all my other consoles and handhelds until near the end of their lives or after they were dead.
NES: Hmm, I dunno, Probably Star Tropics or Castlevania II
SNES: Super Mario World...on my friend's SNES.
PSX/N64: Tactics Ogre:LUCT
PS2/GC/Xbox/DC: Not sure...maybe Front Mission 4?
GBA: Advance Wars (hmm, maybe Advance Wars 2 has surpassed it...?)
PSP: Metal Gear Ac!d
8-bit: Marble Madness/Super Mario Bros. 3
16-bit: Tetris Attack/Earthbound/Chrono Trigger
32-bit: Super Puzzle Fighter II Turbo
64-bit: Goldeneye
Handheld (old): Fire Emblem
Handheld (new): Lumines and Yoshi Touch N Go
128-bit: Thinking...about it...
C64: Adventure Construction Set
NES: Super Mario Bros. 3
SNES: Final Fantasy III
Gameboy: Pokemon Red
Genesis: Phantasy Star IV
PS1: Final Fantasy VII
N64: Mario Kart 64
Game Boy Color: Dragon Warrior III
Dreamcast: SoA, or MvC2
GBA: Wario Ware
PS2: Gitaroo Man
GCN: Super Smash Bros. Melee
NDS: Wario Ware Touched
NES: Super Mario Brothers
SNES: Final Fantasy VI
PSX: Chrono Cross
N64: Perfect Dark
PS2: Gran Turismo 4
DC: Street Fighter III: Third Strike
Xbox: Phantasy Star Online Episode I&II
GCN: Super Smash Bros Melee
PSP: Lumines
This generation: Counter-Strike on the PC
Last generation: Escape Velocity on the Mac
16 bit: Street Fighter II or Final Fantasy VI
8 bit: Dragon Warrior IV
NES: Mario 3, Baseball Stars, Contra, or POW. not one game really sticks out as my most played
Genesis: Road Rash 2, NBA Jam, or Mortal Kombat 2. again not one really sticks out
N64: Goldeneye
PC: Morrowind
all of the above correspond to a different generation, meaning that Morrowind on PC was my most played game this gen and it's not likely that I'll surpass it before this gen ends.
PS: what's with all the Mario 64's? How did you have an N64 and not play Goldeneye for hundreds and hundreds of hours?
Atari - Combat
NES - Double Dragon 2 (I think, maybe SMB)
SNES - Tetris Attack (maybe SSF2)
PSX - Final Fantasy 7 (maybe SFA3)
N64 - Super Mario 64
PS2 - VF4:Evo or Disgaea
PC early 90's - Rune Quake
PC Late 90's - Quake 3 and Unreal Tournament
NES - RBI Baseball
SMS - Quartet
SNES - NHL 94(most played game of all)
Genesis - NHL 93
Saturn - VF2
PSX - Destruction Derby
N64 - Super Mario 64
Dreamcast - NFL2K
PS2 - GTA 3
Xbox - Morrowind
PC - Dark Age of Camelot(giant waste of time)
Current Generation - DC - Soul Calibur
PS2 - Gran Turismo 3
GC - Animal Crossing
Xbox - Halo
GBA - Klonoa 1
DS - Feel the Magic
PSP - Ridge Racers
PC - Counterstrike since 1999
NES - Super Mario Bros. 3
SNES - Probably a toss up between Chrono Trigger, Final Fantasy VI, or Super Mario World
Genesis - Sonic the Hedgehog
Playstation - Final Fantasy VII
N64 - GoldenEye
PS2 - Probably GTA 3
Gamecube - F-Zero GX
XBox - Halo (funny too because I'm not really a big fan of Halo)
Game Gear - Columns
Game Boy - Pokemon Red
Gameboy Advance - Final Fantasy Tactics Advance
NES - Don't remember
Game Gear - GG Shinobi
Megadrive - Don't remember
Mega CD - Don't remember
32X - Doom
Saturn - Dragon Force
Dreamcast - Skies of Arcadia
Playstation 2 - Star Ocean (nearly 200 hours!)
NES: Dragon Warrior III
SNES: Final Fantasy VI
GB/GBC: Dragon Warrior III
GBA: Castlevania: Aria of Sorrow
N64: Super Mario Kart 64
SMS: Phantasy Star
Genesis: Phantasy Star II
SCD: Shining Force CD
32X: Doom
Saturn: Dragon Force
DC: Phantasy Star Online
GC: Phantasy Star Online
PS: Final Fantasy VII
PS2: Final Fantasy XI
PC: Diablo II
ATARI: Tank
NES: Arch Rivals/Super Mario Bros
SNES: SF2/Super Mario Kart/Super Metroid
PSX: Gran Turismo 2
N64: Super Smash Bros/Mario Kart 64
PS2: Guilty Gear X
GC: Smash Bros Melee/Metroid Prime/MKD