Rounding out the multiplayer maps in Gears of War 3 is Gridlock, because of course it is. I have not-so-fond memories of rushing forward and immediately dying in the Gears 1 version of the map. Good times.
In total, we're looking at a decent line-up: Checkout, Drydock, Gridlock, Hotel, Mercy, Old Town, Overpass, Sandbar, Thrashball, and Trenches -- all playable in Versus multiplayer, Beast mode, and Horde mode.
Attached is a gallery full of large images. I lost some of my sanity getting these uploaded, so please take a look.