I guess the other part of this is also that on Twitter I mostly only follow... well, my actual friends. The whole "follow 10,000 people and get a client app to sort what they're saying" workflow just doesn't appeal to me, and it seems that in order to do what you're doing you'd have to follow a huge number of people.
That's the beauty of TweetDeck. I only follow about 20 people. In TweetDeck you can set up additional search columns and it will show you tweets across all of Twitter (updated in real time) that match your search. IMO TweetDeck takes Twitter to another level (and actually makes Twitter useful :) )
