Around here, south Chicago suburbs, I'm finding Google earth to be very accurate. Streets drawn on the map match up perfectly with the street images. If there's something visible from the sky to use as a landmark, like a sidewalk or bridge, I can just print the map and use it to walk right to within 10 to 20 feet of the cache.
Of course, this tactic doesn't work well in the middle of the woods, all the trees look alike from above.