TweetGrid
TweetGrid is for Twitter users who want to process a lot of information very quickly. It lets you search up to 9 different topics, events, converstations, hashtags, phrases, people, groups, etc without refreshing. The information comes through in real time, letting you keep your fingers on the Twitter pulse.
You can create your own layout with TweetGrid, and at any time you can pause the searches you are currently running.
TweetGrid supports pretty much every browser, except for IE6. You can also setup new grids and then share them with other people.
TweetGrid is free to use, and easy to setup.
Check it out at http://tweetgrid.com/
Twitter Grader is a website that gives you a grade out of 100, and compare Tweeple against each other to find out who are the Elite of Twitter.