Glad you brought that up....what is valuable in twitter? The tangential ramblings of a handpicked group? I would argue that only a small subset of even the very best lists actually equates to value for most users.
In the end, it's what's valuable to you. If you can't (or don't want to) find a group of people to follow that you find interesting, helpful, or whatever, that's fine. Just because you (or sharpn, or my wife) don't find the service valuable doesn't mean that there's no value in it for anyone, though.