Do you read a lot? Murder by the Book, the Book Collector, Brazos Bookstore, Halfprice Books, the Lift, Kaboom Books, Becker's Books and the endless Barnes and Nobles stores. There are tons of book stores here.
As a Houstonian, I do beat my chest when I find out Houston is high on a list...but damn, I do wish our population drops. There are way too many people here. Traffic is my biggest complaint.
We're a big city, so yeah you should be able to list a lot of bookstores, but many cities can. And B&N is right out, because everyone has them and they're mostly all the same. Here's a list of 10 great bookstores in Chicago: http://www.chicagotribune.com/lifestyles/chi-0608bestbookstores_jpjun08-story.html#page=1. I'm very familiar with the Hyde Park ones they list: Powell's, which is a smaller but more bookish sort of Halfprice Books; 58th St Books, which I'd take over anything I've seen in Houston; Seminary Co-op, which is just a crazy, crazy place. Those 3 basically exist because of the University of Chicago community. Rice has some bookstores in its footprint, but they don't seem to cater to the Rice community in the same way (though it may only appear that way to me because I was only an MBA student there), and not nearly as bookish as a result. I won't say Chicago's the best or anything, because I really don't know. But, I have a really hard time buying Houston as #2 here.