The majority of the top comments are quite good, and it'd be a shame to lose a prominent link to them.

Jack's open thread test, RobinZ's polling karma balancer, Yvain's subreddit poll, and all top-level comments from The Irrationality Game are the only comments that don't seem to belong, but these are all examples of using the karma system for polling (should not contribute to karma and should not be ranked among normal comments) or, uh, para-karma (should contribute to karma but should not be ranked among normal comments).