For quite some time I have successfully ignored Twitter and regarded it as just another form of celebrities promoting themselves (probably through the same PR companies also writing their blogs for them) and random people yelling the state of their digestion into the world.
Of course, there are the types I mentioned above, but I quickly learned there are lots of interesting bits of information flying around. I just started by following the JavaPosse, the BitsUndSo members, Scott Hanselman and a few others and very soon got interesting (and of course irrelevant as well) tweets to read.
Since then I tried out several Twitter clients, but so far I stuck with TweetDeck, because I like the display very much - this and the fact that there is an iPhone version as well. Yes, sometimes that latter one still crashes, but overall I find it quite usable, especially with the recently added "sync-my-searches" option that helps keep iPod, private Mac and work Windows PC up to date configuration-wise.
Feel free to follow me, I try to keep the signal to noise ratio attractive.