Plot + character = beginning

Sometimes people ask whether character or plot comes first. I've discovered that I need both in order to write. Plot is what happens; I can't write without it, because otherwise the characters have nothing to do. But I also need a voice in which to tell the story. I need a protagonist with whom I'm willing to spend a couple of years of writing, revising, and just plain thinking. Let's face it, book characters are almost like roommates or family--they live with you; you worry about their fates...