I probably buy ~15 books per year (but read only 10-12). Here's the way I shop for and buy books.
I find books that interest me via reviews, recommendations and browsing in book store and then I go to Amazon and put it on my wish list.
Then, I usually wait until I get a 40% off electronic coupon sent to me by Borders and then I go to my local Borders and buy one. Or, I buy it on Amazon at 30+% discount or from a reseller at a very deep discount. By the way, I buy very little from either retailer besides books.
So, am I a good customer or a terrible customer? Can you be a good customer if you generate no profit?
It all comes down to the metrics you use to determine what you value in a customer, and those metrics may go beyond sales and profit dollars, like frequency of visit, size of purchase, involvement with brand (writes reviews), refers others to brand, lifetime value vs. individual transaction value, community involvement, does this customer have a blog or lead a tribe, how big is his family.
Would you fire me as a customer? What metric do you use to decide when to keep or fire a customer?
O.D.O.o.O.D.B.