I have actually done quite some research into HN's and Reddit's algorithms (i.e. http://amix.dk/blog/post/19574 and http://amix.dk/blog/post/19588 ) and I would say that using The Wilson score confidence interval would improve HN's comment sections a lot.
The real meat is here: http://www.evanmiller.org/how-not-to-sort-by-average-rating....
Even if it looks hairy it's fairly simple to implement in e.g. Python (from Reddit's code, rewritten from PyRex): https://gist.github.com/amix/5230165
Maybe pg could try this out for a few days and we could see what the results are!