Many free and reduced price items available for download on the PC Xbox Live Marketplace, including the Gold Plated Lancer, exclusive Gamestop Gears of War 2 Theme, and Call of Duty World at War Day One Advantage.

Call of Duty 4: Modern Warfare
Call of Duty 4: Modern Warfare - Prestige Icons Picture Pack


Call of Duty: World at War
CoD: World at War - Day 1 Tactical Edge
CoD: World at War: - Collector’s Edition Tactical Edge

Gears of War
Gears of War - Gears of War Emergence Day Message from Cliffy B (720p)
Gears of War - Emergence Day Theme
Gears of War - Emergence Day Gamer Picture

Gears of War 2
Gears of War 2 - Gold-Plated Lancer Assault Rifle
Gears of War 2 - Gamestop Exclusive Theme


Guitar Hero III
Guitar Hero III: Dream On by Aerosmith

Halo 3
Halo 3 - Bungie Day '08 Theme!
Halo 3 - Bungie Day '08 Gamerpics
Halo 3 - Bungie Day 2007 Theme
Halo 3 - Bungie Day 2007 Picture Pack


The Last Remnant
The Last Remnant - March To War Set (Pre-order extras, 100 M$)


Left For Dead
Left For Dead - Demo


Lumines Live!
Lumines Live! - Heavenly Star Skin
Lumines Live! - Breeze Skin


Test Drive Unlimited
Test Drive Unlimited - Pagani Zonda C12S Roadster + McLaren F1
Test Drive Unlimited - Lamborghini Gallardo Coupe


Tom Clancy's EndWar
Tom Clancy's End War - FirstWar Enlistment Pack


Xbox Live ARCADE Games [Firestorm Note: You still pay 1200 points but get it early like the cool people (ie. me) who pre-ordered]
Banjo-Kazooie - Get it early, before release on 12/3/08


99999 MS Points
Fable II - Limited Edition Content
Gears of War 2 - Flashback Map Pack
Gears of War 2 - Gold Plated Hammerburst
Halo 3 - Exclusive Xbox 360 Halo 3 Special Edition Gamer Pics
Halo 3 - Exclusive Xbox 360 Halo 3 Special Edition Theme
Rock Band 2 - Bonus tracks


Free stuff that is easily available on XBL


BioShock
Ryan Industries Plasmids and Gene Tonics

Xbox Live Arcade Games
TotemBall

Lost Odyssey
Lost Odyssey - Double Bonus Pack