update: I went back to Half Price Books in July 2012 and found it no longer smelled like smoke. This may be due to the air conditioning running non-stop in summer whereas before when I visited in March the a/c was minimal. I had more chance to look around ... many interesting books, but many interesting book are not there. So I wasn't totally enchanted. The trade policy states cash only, so you don't get to trade a used book for half of it's expected selling price like at Changing Hands.