Capcom : Resident Evil 4

Ubisoft : Tom Clancy's Splinter Cell

Square-Enix : Chrono Trigger

Rare : Donkey Kong Country 2: Diddy's Kong Quest

Nintendo : The Legend Of Zelda: Majora's Mask

EA : NHL 10

Activision / Blizzard: Call Of Duty: World At War

capcom : Resident evil

ubisoft : beyond good and evil

square-enix : final fantasy series

namcobandai : Tekken

mistwalker : never played any of their games

rare : Goldeneye

nintendo : Mario

EA : FIFA

activision : call of duty series

id software : doom series

from software : Tenchu

Capcom : Resident Evil

Ubisoft : Assassins Creed

Square-Enix : Final Fantasy

Namcobandai : Tekken or Soul Calibur

Mistwalker : Blue Dragon (yeah but Lost Odyssey is a close second)

Rare : Donkey Kong Country

Nintendo : Pokemon

EA : too many great game series. Probably Battlefield

Activision : Call of Duty

id software : Doom

From Software : Ninja Blade

capcom : Street Fighter series, I guess.

ubisoft : Splinter Cell series

square-enix : n/a

namcobandai : Tekken series

mistwalker : n/a

rare : Goldeneye 007

nintendo : Zelda series

ea : Burnout series (before Paradise)

activision : Call of Duty series

id software : Doom

from software : Looks like it would be Demon's Souls, but I haven't played it.

sega : Sonic the Hedgehog series (back when it was good)

konami : Metal Gear Solid 4

EDIT:

Blizzard: Warcraft III

Sony: God of War series AND Shadow of the Colossus (tie)

2K: BioShock

EDIT 2, to make Ronster happy (kind of):

Valve: Left 4 Dead.

Some are obviously only publishers, others are developers, but based on the list of companies available...................


Capcom: Resident Evil 2
Ubisoft: Splinter cell (xbox)
Square: N/A
Namco: Ridge Racer Type 4
Mistwalker: N/A
Rare: Killer Instinct
Nintendo: Super Mario World
EA: Tiger Woods 06
Activision: Tony Hawks Pro Skater 3
Id: Has to be Doom of course
From software: Only played Ninja blade so obviously that one wins for now.
Konami: Metal Gear Solid (PS1)

Theres some MAJOR companies missing from the list though.......... companies like....... (My fave game in brackets)

Sega (Shenmue)
Treasure (Guardian Heroes)
Rockstar (GTA: Vice City)
2K (NBA 2K8)
Valve (Left 4 Dead) ect ect.

Capcom : Street Fighter IV

Ubisoft : Assassins Creed

Square-Enix : Kingdom Hearts 2

Namco Bandai : Tekken 5

Mistwalker : None

Rare : None

nintendo : Pokemon Diamond/Pearl

EA : Crysis

Activision : Call of Duty 4: Modern Warfare

id software : Doom

From Software : Demon Souls

Sega : Valkyria Chronicles

Konami : Metal Gear Solid 4: Guns of the Patriots

The list above shows the games that I've played in which I consider the best from each company. If I was to include upcoming games, then the list would be quite different.

capcom : time crisis

ubisoft : assassins creed

square-enix : final fantasy series

namcobandai : dragon ball z, Japanese anime games

mistwalker : lost odyssey

rare : killer instinct

nintendo : pokemon

ea : fifa series

activision : call of duty series

id software : doom series

from software : demon souls

sega : sonic

konami : metal gear solid 4

What do you mean "Rare: none"!? They're only one of the greatest developers of all time. You should be spoilt for choice!

Let's see.

Capcom: Ace Attorney Series

Ubisoft: Assassin's Creed Series

Square-Enix: Final Fantasy Series

Namco-Bandai: Tales of Series

Mistwalker: Lost Odyssey

Rare: Banjo-Kazooie I guess? But I don't really like anything they do nowadays.

Nintendo: The Legend of Zelda Series

EA: I honestly have no idea.

Activision-Blizzard: Starcraft Series

ID Software: Quake Series

From Software: I don't think I've ever played a game from them.

Sega: Sonic Series, I suppose

Konami: Castlevania Series