Ranking forum posts by popularity

I want to allow users to rate forum posts, either a star rating system or as a thumbs up/thumbs down sort of deal. I would also like the posts to be ordered by popularity if possible or to at least have the most popular posts displayed as stickies at the top of the thread.

My original intention was to use Drupal for this purpose, but I think it might be easier to use WordPress instead. Any input would be greatly appreciated. Thanks.