Have you explored MapThatPad (www.mapthatpad.com) ? It's not your everyday listing site, but an apartment hunting organizational tool. It takes 2 steps to easily pull in and map as many listings from Craigslist, streeteasy, Oodle, NYtimes and other sites. You can share your maps and invite friends to collaborate on your hunt. Not to mention, that you can see all important nearby amenities such as restaurants, groceries and transit (for NYC and SF).