Little Boxes by Pete Seeger.Usually your hear the live version with an audience of smug middle-class lefties tittering in the background.
Horse With No Name,that someone above mentioned is bloody awful too,because of its pretentiousness.
Black Velvet Band is often murdered because people are under the misapprehension that its an irish song,(its english)so they copy the Dubliners' ghastly interpretation.Its one of those songs that is great to sing - but not always so great to listen to.