EBGames/Gamestop have posted what you will be getting in the Limited Edition version of Gears of War 2:

Gears of War 2: Limited Edition

Get your hands on the most complete Gears of War 2 experience available! The Gears of War 2: Limited Edition includes the following bonus materials:

• Collectible SteelBook™ DVD case
• "Beneath the Surface: An Inside Look at Gears of War 2," a 48-page hardbound book including character profiles, exclusive concept art, and foreword by Design Director Cliff Bleszinski
• Bonus DVD including exclusive making-of-the-game video footage, design galleries with audio commentary by Epic Games, and promotional videos including the E3 2008 trailer,
"Rendezvous."
• An exclusive gold-plated Lancer Assault Rifle available during online play

One thing they forgot to add was a picture of Dom and I would guess his wife, if he has one. Is this worth the extra $10? I think so. I already have my pre-order in. And I can't wait to show off my gold-plated Lancer Assault Rifle online. :D