Firefox 3 smart folders
The third in an unbounded set of the things I love about Firefox 3. There's a new backend for history and bookmarks (called "Places") that makes things way faster and easier to do neat things with, like search and statistics. The Page Info dialog's number-of-visits value, for instance, is definitely pulled from there. Firefox 3 also comes pre-configured with some smart folders like these.
Firefox 3 beta 1 is in testing right now and may be released soon. If you're interested in seeing the pending awesomeness for yourself, you should give it a whirl when it lands.