Here's another thing I'd like to share. I use this for when I want to focus on a particular area somewhere in the world and give the area of play some rough boundaries.
http://wikimapia.org/country/
This is pretty much a database of locations all around the world, from Afghanistan all the way to Zimbabwe. What I do is that I select a place in a state/province in a country, and I'll use the places listed under said place as a rough boundary of my RP.
Just a word of advice though, I'd still recommend using your imagination to fill the gaps, so to speak. The locations listed under each place can range from only covering schools and fast food chains to being absolutely cluttered with random placemarks. You'll find the latter quite often in the Middle East, North Africa, the Indian subcontinent, and Southeast Asia. For example, if you wanted to do something in the vein of The Walking Dead, you'd probably want to cross reference with Google Maps, Panoramio, and 360 Cities. Random houses and other unmarked locations can be interesting places too. Though if you were doing random houses and other private addresses, you'd probably want to make them up. It's nice to have the real world as a big reference for your RP, but it can also be pretty creepy to use somebody's real address for your RP.