I am often in a hurry and find I can have the books I need for my research shipped to me using 2 nd day air and still save money because of the huge discounts on their books. I once ordered the same book from amazon and from the other afore-mentioned large chain. At any rate, I recommend Amazon Bookstore heartily, and since I have become so indebted to them, I now have to sell books to defray the cost of my own personal book addiction. In addition to my favorite online bookstore, I often use these other fine online services for the sake of price and availabilty comparisons.
Competition keeps the marketplace honest.