I tried using a stack of index cards instead of an initiative tracker last session, and it worked out pretty well. I put most of the monster stats on each card, plus checkboxes for hit points. I think it was smoother than using the tracker.
I may need to put more of the stats on each card; I kept having to go back to the book. Maybe only for more or less simple monsters, and Big Bads can still require book reference?
I really like the ease of having defenses and hit points all in hand, though. The checkboxes in particular fit how my mind works.