In your opinion.
Wii:
SSBB
SMG
MadWorld
Xbox 360:
Halo 3
Gears Of War 2
Halo Wars
PS3:
Little Big Planet
MGS4
Saints Row 2

Haven't played many games but whatever. I'll only do systems I've played at least 10 games on.
NES
Super Mario Bros 3
Kirby's Adventure
Tecmo Bowl

Game Gear
Madden 95
Tails Adventure
Sonic Chaos

Genesis
Sonic and Knuckles
Sonic 2
Sonic 3

Gamecube
Super Smash Bros Melee
Sonic Adventure 2 Battle
Aonic Adventure DX

Gameboy Advance
Sonic Advance
Kirby And the Amazing Mirror
Mario and Luigi: Superstar Saga

DS
Animal Crossing: Wild World
Sonic Rush Adventure
Mario And Luigi: Partners in Time

Wii
Super Smash Bros Brawl
Super Mario Galaxy
Super Paper Mario

2600: Fast Eddie
Jaguar: Zool 2
NES: Super Mario Bros. 3
SNES: Super Mario World
N64: Zelda Majora's Mask
GC: Pikmin
Wii: Super Mario Galaxy
GB: Super Mario LAnd 2: 6 Golden Coins
GBC: Pokemon Silver/Gold
GBA: Sonic Advance 3
DS: Sonic Rush
Gen: Sonic 3
Sega CD: Sonic CD
32X: Knuckles Chaotix
Sat: Sonic Jam
DC: Sonic Adventure
GG: Sonic Triple Trouble
Xbox: Jet Set Radio Future
360: Sonic Unleashed
PS1: Spyro 2: Ripto's Rage
PS2: Kinetica
PS3: Killzone 2
PSP: Twisted Metal: Head On

I'm certainly not doing a list for every system I own.

NES:megaman 2

snes:super mario all stars

Genesis:sonic 2

ps1:crash and spyro series

dreamcast:SA1

ps2:ace combat 5

wii:
battalion wars 2

NES: Mega Man 2

SNES: Donkey Kong Country 2

Mega Drive: Sonic 2

Game Gear/ Master System: Sonic 1

PS1: Rayman

GameCube: Sonic Adventure DX

Game Boy: Pokemon Yellow

Game Boy Color: Pokemon Crystal

Game Boy Advance: Super Mario World: Super Mario Advance 2

DS: Mario Kart DS

Wii: Sonic & the Secret Rings

NES: Super Mario Brothers 3
SNES: LOZ: A Link To The Past
GEN: Sonic 3 and Knuckles
N64: LOZ:Ocarina of Time
Sat: NiGHTS: Into Dreams
PS1: MegaMan Legends
PS2: Sly Cooper and the Thevius Raccoonus
DC: Shenmue or Jet Grind Radio
GC: LOZ: Windwaker
XBOX: Shenmue 2 or Jet Set Radio Future
Wii: Super Mario Galaxy
360: Burnout Revenge
PS3: Ratchet and Clank Future
GB: LOZ: Link's Awakening
GBA: LOZ: The Minish Cap
DS: LOZ: Phantom Hourglass
PSP: FFVII: Crisis Core

Mighty wrote:NES: Super Mario Brothers 3
SNES: LOZ: A Link To The Past
GEN: Sonic 3 and Knuckles
N64: LOZ:Ocarina of Time
Sat: NiGHTS: Into Dreams
PS1: MegaMan Legends
PS2: Sly Cooper and the Thevius Raccoonus
DC: Shenmue or Jet Grind Radio
GC: LOZ: Windwaker
XBOX: Shenmue 2 or Jet Set Radio Future
Wii: Super Mario Galaxy
360: Burnout Revenge
PS3: Ratchet and Clank Future
GB: LOZ: Link's Awakening
GBA: LOZ: The Minish Cap
DS: LOZ: Phantom Hourglass
PSP: FFVII: Crisis Core

You must be a big Zelda fan, huh?