The only way Twitter is compelling is if you can convince your entire group of friends to use it too. Then it takes on use value. Otherwise, it is pretty useless.
Here is my well thought out hierarchy
Friends > friends of friends > "in the know" locals who you don't really know (great for advertising shows - twitter people attendance is usually way high percentage wise - you thought facebook groups were good for this) > People you kind of know online (I've followed the guy from Smashing Transistor for a year now, and "'know" him a lot better now) > Insane celebs (Shaq) > People pretending to be celebs (exception: fake michael bay, which is the best thing ever) > random strangers > famous bloggers > "social networking gurus" > relatives.