there's a dangerous, corrupting influence in the neighborhood, threatening my very way of life.
srsly? jules, how are these people a threat? sure, they're repugnant, scheming low-lifes - but that's a mild disturbance, not a threat. are you concerned that they'll raid your abode and steal stuff? take you hostage fro ransom? make you join them on that street corner?!? what?!?
btw, you asked "My neighbors are big, fat liars. Advice?". the only thing you can really work on is the "fat" part. i suggest you take an interest in their eating habits (cut out fats and processed carbs, up the fruit and veg), maybe invite them on your morning jogs, encourage them to seek a weight-loss support group if they're in to that kind of thing, etc.