I think Circus Ponies Notebook works very well for law school note taking. It's speedy, has a good, clean interface, and is nicely consistent in how it sticks to the notebook metaphor. My one complaint is that the index/search feature feels clunkier to me than normal spotlight-style searching.
I switched over to it during 1L year after realizing that Word's "notebook" feature got incredibly laggy after you had more than a couple week's worth of notes on it.