Have:
XBLA Games:

Family Game Night: Scrabble

Puzzle Chronicles

Backbreaker Vengeance

Toy Soldiers: Cold War

Dungeon Defenders

Daytona USA

Space Channel 5 Part 2

BloodRayne: Betrayal
DLC:

Dragon Age: Awakening

Dragon Age: Blood Dragon Armor

Borderlands: The Secret Armory Of General Knoxx

DJ Hero: Tiesto Mix Pack

Vanquish: Tri-Weapon Pack

Fable III: Channeler Sword

Mortal Kombat: Online Pass

Assassin's Creed Brotherhood: Trajan Market (in-game, not sure if works)

Rock Band 2: Export Code

Band Hero: Export Code

Duke Nukem: Hail To The Icons pack

Batman Arkham City: Batman Beyond skin

Forza 4: Limited Collector's Edition DLC (1 code includes VIP, American Muscle, Launch Bonus, and BMW Design Challenge car packs)

Halo Reach: Legendary Edition DLC code (1 code includes Flaming Helmet, Elite Officer armor, Falcon prop, Recon Helmet)

Halo Reach: Recon Helmet

Alan Wake: The Signal

Kinect Joyride: Hammerhead, Apex, Sphinx, Eisenberg

Halo 4: Bulletproof emblem, Longbow theme
Avatar Stuff:

Assassin's Creed 2 Ezio Outfit (from Slurpee promo) (F)

CoD: Black Ops Flight Suit (M)

CoD: Black Ops R/C XD prop

Soccer Ball

Spring Tree

Halo Energy Sword

Halo Banshee

Halo Master Chief Armor

Black Controller

Community Xperts Kinect Prop (same as Gamestop one?)

Carrot Plush Mascot

Foam Finger

Kinect Adventures Helicopter

Forza 4 "I AM THE STIG" shirt

Halo 4 Ghost prop
Want:

Monaco

Dungeons & Dragons: Chronicles of Mystara

Charlie Murder

Double Dragon Neon

Shank 2

Xbox Live Gold codes (not 48h)

Microsoft Points

Halo 4 Maps

PSN credits

Spelunker HD

Tokyo Jungle
Only looking for the above.
These are pretty much the only things I'm looking for at the moment, and I don't plan on trading XBLA codes for anything else... Just to save both you and me some time