"Favorite" Module for drupal 7
I was thinking that would be a great idea, until I remembered that Drupal contributors have already offered quite a few solutions for this as demonstrated by a quick search of the Drupal site. Of course, Flag module provides a great abstract way of creating these types of systems. There's also Favorites and Add to favorites, but those are for Drupal 6 only right now. I would recommend Flag I think just because I've used it for precisely this type of thing as have many others (even though it's still in beta), and quicksketch and fago are great Drupal developers.