Definite Day 1 buys already are...
Bulletstorm (360)
Crysis 2 (360)
Deus Ex:Human Revolution (360)
Duke Nukem: Forever (360)
Rage (360)
Gears of War 3
Mass Effect 3 (360)
Elder Scrolls V: Skyrim (360)
Metal Gear Solid: Rising (360)
Aliens: Colonial Marines (360)
& maybe Killzone 3, Resistance 3 & Zelda: Skyward Sword
Eventual buys (after price drops & rentals)....
Dead Space 2 (360)
Dungeon Siege 3 (360)
inFamous 2
Forza Motorsport 4
NCAA Football 2011 (360)
LA Noire (360)
Two Worlds 2 (360)
Project Draco
No More Heroes: Paradise (TBD)
Codename D
Venetica (360)
Test Drive: Unlimited 2 (360)
Marvel VS Capcom 3: Fate of Two Worlds (360)
Mortal Kombat (360)
Dragon Age 2 (360)
Ico/Shadow of the Colossus Collection
Earth Defense Force: Insect Armageddon (360)
Child of Eden (360)
Brink (360)
Driver: San Francisco (360)
Shift 2 Unleashed (360)
Record of Agarest War Zero (360)
FEAR 3 (360)
Homefront (360)
Hunted: Demon`s Forge (360)
The Cursed Crusade (360)
Catherine (360)
Ace Combat: Assault Horizon (360)
True Crime: Hong Kong (360)
Tomb Raider (360)
Ghost Recon: Future Soldier (360)
Batman:Arkham City (360)
Warhammer 40,000: Space Marine (360)
Shadows of the Damned (360)
Kingdoms of Amalur: Reckoning (360)
Max Payne 3 (360)
Spec Ops:The Line (360)
Uncharted 3: Drake`s Deception
Lord of the Rings: War in the North (360)
Red Faction: Armageddon (360)
The Witcher 2 (360)
EDIT: After looking over my most wanted list and Day 1 buys...2011 is definitely going to be ruled by strong multiplatform titles all year. Also the strongest year for large AAA caliber shooters ever this generation. Last time so many great shooters came out in a single year was back in 2004.
How our favorite systems are just like humans and sometimes have issues finding their special someone...
Xbox 360 wants to Kinect & PS3 wants to Move! Why are both systems having such relationship problems? The reason is they both become so infactuated with desire while watching the Wii as it waggles on by. They simply want what they can't have.