New Super Mario Bros. Wii
Mario & Luigi 3
Spirit Tracks
Uncharted 2
Modern Warfare 2 (360)
Bioshock 2 (360)
NHL 10 (360)

maybe Assassin's Creed 2, Scribblenauts

DEFINITIVE PURCHASE:
On my Xbox360:

Fall 2009:

• CRACKDOWN 2
  
• Forza Motorsport 3
• Splinter Cell Conviction

Winter 2010:

• Mass Effect 2

On my PS3:

Fall 2009:

• Uncharted 2
  

Winter 2010:

• Don't know yet...

Assassins Creed 2
Bioshock 2
UnCharted 2
Modern Warfare 2
Only game without the number 2 I will be buying is.....
Splinter Cell: Conviction

Assuming Spirit Tracks, New Super Mario Bros Wii and Mario and Luigi 3 come out in the fall, one of those, while the others are for Christmas.

scrriiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiibbbleeenauts

Halo 3:ODST, Forza 3, Persona (for PSP, if I purchase one), Star Oceans for PSP, Magna Carta II (I think this comes out then).... hmm others that I can't currently think of at the moment. Lol, and I will still buy Left 4 Dead 2... love the game despite the lack of support ;) I am forgetting a lot of the other ones.

360:
Forza3,
Halo ODST,
Tales of Vesperia,
WET,
Bayonetta,
Shadow Complex,
KOFXII(if i will find one for reasonable price)
WII:
Rune Factory: Frontier,
Muramasa: Demon Blade,
Tiger Woods PGA 10,
Endless Ocean 2: Beautiful Ocean,
it's good to have many wii owners friends so i don't have to buy many games:D
PSP:
Gran Turismo Mobile,
Dissidia: Final Fantasy,
Shin Megami Tensei: Persona,
SOCOM: U.S. Navy Seals Fireteam Bravo 3,
Holy Invasion of Privacy, Badman!What Did I Do To Deserve This?

and one of those games if they will be for cheap by the end of 2009:
Harvest Moon: The Sugar Village & Everyone's Wishes,
Motorstorm: Arctic Edge,
Soul Calibur: Broken Destiny,
30 Second Hero,
Fat Princess: A Fistful of Cake,

those are the games i will buy in the rest of 2009(rest of them i will get later when they will be cheaper). it's a pain to have more than 1 console - you just don't have money or time to play all those games.

DEFINITE:

Uncharted 2

Ratchet and Clank Future: ACIT

Modern Warfare 2

BioShock 2

MAYBE (ranging from likely to possible):

MAG

Assassin's Creed 2

Something on PSP

PS3:
Uncharted (surely they'll drop the price to Greatest Hits before the sequel is released)
Uncharted 2
Bioshock 2
Assassin's Creed 2
GT5 (if it does come out this fall)

PSP:
PSP Go
GT Mobile
FF Dissidia

Uncharted 2, Bioshock 2, Tekken 6, Max Payne 3, Splinter Cell Conviction, R & C, Halo ODST, MAG, maybe Demons Souls. That's just on consoles, not sure about handhelds.