wii:SSBB
Gamecube-SSBM or The thousand year door.
N64-Ocarina of time.
SNES- Super Mario World
PS2- Not shure so many great ones.
PS1- 1st spyro game?
PC- black and white.
GB- not shure
GBA- superstar saga
DS- New SMB

Consoles I have
wii: SSBB
GCN: FE:PoR
N64: Banjo-Kazooie
GBA: FE:TSS
DS: Kirby Remake
GBC: Pokemon Red

Consoles I don't have
ps3: R & C
ps2: Kingdom Hearts
psx: Spyro
360: Banjo Kazooie 3
XBOX: GTA: Double Pack

Wii: Super Smash Brothers-Only beats Mario because of its never ending appeal for multiplayer.
360: Orange Box-Kind of cheating, but Half-Life 2 is awesome, and so are the rest of the games included.
GC: Super Smash Brothers-Again, multiplayer fun never ends. Resident Evil 4 is a close second.
N64: Legend of Zelda: Ocarina of Time-The greatest game of all time.
SNES: Chrono Trigger-Best RPG ever made, with lots of replay value due to the many endings. Super Mario Allstars would be my second choice, with 4 games in 1 (5 if you get the version with Super Mario World!).

a lot of people are saying brawl here, it's not out yet, no one has played it, how do you know if it is good?, it will be good though, no doubt

Future games:

PS3: Resistance 2
PSP: God of War: Chains of Olympus

360: GTA 4 (will not own a 360 ever again though, will get the PS3 version)
(Wii: True Mario 64 successor game could push me into getting a Wii, like I bought the N64)

PS3: Final Fantasy XIII
X360: Halo 3
Wii: Super Smash Bros. Brawl

PSP: Crisis Core: Final Fantasy VII
DS: The Legend of Zelda: Phantom Hourglass

Wii- Carnival Games
360- Viva Pinata
PS3- Lair
DS- Metriod Pinball (EA Playground is close second)
PC- Sim Turkey Farmer

I chose SSBB due to what we've seen of it already, all the added meterial, and the greatness of it's predecessors.