Just for fun, listing the announced exclusive stuff so far....
PlayStation 2
-Adversary (Namco)
-Altered Beast (Sega)
-Dark Cloud 3 (SCEA/Level 5)
-Champions: Return to Arms (SOE/SnowBlind)
-Cold Fear (Namco/DarkWorks)
-Enthusia: Professional Racing (Konami/KCES)
-Final Fantasy XII (Square Enix)
-FullMetal Alchemist and the Broken Angel (Square Enix/Racjin)
-Getaway: Black Monday (SCEA/Studio Soho)
-God of War (SCEA/Santa Monica Studio)
-Kingdom Hearts II (Square Enix)
-Musashi: Samurai Legend (Square Enix)
-NanoBreaker (Konami/KCET)
-Phantom Crash 2050 (Konami/Genki)
-Resident Evil Outbreak: File 2 (Capcom)
-Rise of the Kasai (SCEA/BottleRocket)
-Sega Ages: Phantasy Star Trilogy (Conspiracy/D3)
-Tekken 5 (Namco)
-Tomb Raider VII (Eidos/Crystal Dynamics)
-Xenosaga Episode II: Jenseits von Gut und Bose (Namco/Monolith)
XBox
-B.C. (MGS/Intrepid)
-Conker: Live and Reloaded (MGS/Rare)
-Jade Empire (MGS/Bioware)
-Kameo: Elements of Power (MGS/Rare)
-Kore Gang (CDV/UDS)
-MechAssault 2: Lone Wolf (MGS/Day 1)
-Resonance (tba/NoCell)
-WWE Wrestlemania XXI (THQ/Studio Gigante)
-XTango: Shuffling Roses (tba/BinarySoft)
GameCube
-Advance Wars: Under Fire (Nintendo/Kuju)
-Donkey Kong: Jungle Beat (Nintendo)
-Fire Emblem (Nintendo/Intelligent Systems)
-Geist (Nintendo/n-Space)
-Harvest Moon: A Wonderful Life for Girls (Natsume/Marucome)
-Killer 7 (Capcom)
-Legend of Zelda (Nintendo)
-Mario Party 6 (Nintendo/Hudson)
-Mario Tennis (Nintendo/Camelot)
-Odama (Nintendo/Vivarium)
-Resident Evil 4 (Capcom)
-Unity (Lionhead/LamaSoft)
GameBoy Advance
-Donkey Kong: King of Swing (Nintendo/Paon)
-Dragon Ball GT: Transformation (Atari/tba)
-Dragon Ball: The Red Ribbon Army Saga (Atari/tba)
-Legend of Zelda: The Minish Cap (Nintendo/Capcom)
-Mario Tennis (Nintendo/Camelot)
-Shantae 2: Risky Revolution (tba/WayForward)
N-Gage
-Glimmerati (Nokai)
-Rifts (Nokia/Backbone)
-Xanadu Next (Nokia/Nihon Falcom)
...did I miss anything notable?
PlayStation 2
-Adversary (Namco)
-Altered Beast (Sega)
-Dark Cloud 3 (SCEA/Level 5)
-Champions: Return to Arms (SOE/SnowBlind)
-Cold Fear (Namco/DarkWorks)
-Enthusia: Professional Racing (Konami/KCES)
-Final Fantasy XII (Square Enix)
-FullMetal Alchemist and the Broken Angel (Square Enix/Racjin)
-Getaway: Black Monday (SCEA/Studio Soho)
-God of War (SCEA/Santa Monica Studio)
-Kingdom Hearts II (Square Enix)
-Musashi: Samurai Legend (Square Enix)
-NanoBreaker (Konami/KCET)
-Phantom Crash 2050 (Konami/Genki)
-Resident Evil Outbreak: File 2 (Capcom)
-Rise of the Kasai (SCEA/BottleRocket)
-Sega Ages: Phantasy Star Trilogy (Conspiracy/D3)
-Tekken 5 (Namco)
-Tomb Raider VII (Eidos/Crystal Dynamics)
-Xenosaga Episode II: Jenseits von Gut und Bose (Namco/Monolith)
XBox
-B.C. (MGS/Intrepid)
-Conker: Live and Reloaded (MGS/Rare)
-Jade Empire (MGS/Bioware)
-Kameo: Elements of Power (MGS/Rare)
-Kore Gang (CDV/UDS)
-MechAssault 2: Lone Wolf (MGS/Day 1)
-Resonance (tba/NoCell)
-WWE Wrestlemania XXI (THQ/Studio Gigante)
-XTango: Shuffling Roses (tba/BinarySoft)
GameCube
-Advance Wars: Under Fire (Nintendo/Kuju)
-Donkey Kong: Jungle Beat (Nintendo)
-Fire Emblem (Nintendo/Intelligent Systems)
-Geist (Nintendo/n-Space)
-Harvest Moon: A Wonderful Life for Girls (Natsume/Marucome)
-Killer 7 (Capcom)
-Legend of Zelda (Nintendo)
-Mario Party 6 (Nintendo/Hudson)
-Mario Tennis (Nintendo/Camelot)
-Odama (Nintendo/Vivarium)
-Resident Evil 4 (Capcom)
-Unity (Lionhead/LamaSoft)
GameBoy Advance
-Donkey Kong: King of Swing (Nintendo/Paon)
-Dragon Ball GT: Transformation (Atari/tba)
-Dragon Ball: The Red Ribbon Army Saga (Atari/tba)
-Legend of Zelda: The Minish Cap (Nintendo/Capcom)
-Mario Tennis (Nintendo/Camelot)
-Shantae 2: Risky Revolution (tba/WayForward)
N-Gage
-Glimmerati (Nokai)
-Rifts (Nokia/Backbone)
-Xanadu Next (Nokia/Nihon Falcom)
...did I miss anything notable?