Been playing around with TweetDeck, a Twitter desktop client. This lets you not only read your Twitter stream, but also split your stream into separate streams for just certain groups of folks (personal friends, business contacts, etc.).
It works well for its stated purpose, though the tweets take up a lot of space compared to, say, the main Twitter website. So you can only see 6–7 tweets per column, though I can see 4 to 5 columns at once.
But the big advantage is that you get a more comprehensive view of Twitter traffic. You see recent messages meant specifically for you, your friends’ conversations, etc. — all at a glance.
Of course, it’s only useful if you like Twitter. But if you do, TweetDeck’s worth considering.