I 'third' the comments above regarding jumping kml vs. entering actual coordinates.
I've done a ton of caches on GE (before I had a GPS unit) and have found it to be, as they say, "dead-on balls accurate" (apologies to Marissa Tomei).
The satellite imagery can be a little off, as we've seen, but most of the stuff around here has good data, so it helps. I'm betting the roads are more accurate than the pictures, too...