I tend to not worry about titles until the end of my editing phase. I name drafts after the main characters and, by the time I wrap up edits, an actual title usual emerges. I also get a kick out of playing with chapter titles - some of my books have only numbers, others have phrases. I know some folks use quotes, too.
So, here are a couple "You Tell Me" questions. What do YOU think about books titles and chapter titles?