The neighborhoods around downtown Vegas (a little east of the Stratosphere) has a "ghetto" look to it, with old buildings, cracked sidewalks, and a 'destroyed' kind of feel to it. Mt. Charleston (just an hour away) is great for any woods/foresty pics.
Also, I'm not familiar with Borderlands, but if you need any winter/city areas, the Venetian and Palazzo are doing a "Winter in Venice" monthlong event. They'll be decorating the entire two casinos (generally great for Steampunk/Victorian settings) and giving them a very wintery feel.