I haven't done much thinking about Twitter lists yet, but I did stumble upon this very elegant and smart way to use them. I like that the lists are completely relevant to the profile and answer questions you would like the answer to.
While we are highlighting the smartness of Work [at] Play...you must check out their site.
I love how the background (image of them working) is supporting and standing behind the work (it pops over the background) nice little metaphor. I'm also really into the horizontal movement when you navigate.