Like most big cities, Houston has a wide variety of hospitality options. Downtown, you'll find many national business-class hotels (Doubletree, Hilton, Hyatt, Four Seasons) geared for traveling workers and conventioneers, plus some pretty fabulous independent properties. Most are connected to the underground tunnel system and/or skybridges, so it's easy to get around in climate-controlled comfort
(you can access the tunnel system via most large buildings downtown). The majority of Houston's other hotels are in the Uptown/Galleria area, with shopping and entertainment attractions. If hitting Neiman Marcus and Saks Fifth Avenue is your thing, this is the place for you. This also seems to be where the international set nests, especially vacationing Mexicans and South Americans.
At certain times of the year, like during the Houston Livestock Show and Rodeo in March and during large trade shows and conventions like technology-centered OTC and ITEC, both in May, Houston's hotel rooms fill up quickly, so call ahead to see what's going on that month. When the city hosted the Super Bowl in 2004, every hotel room in Houston was taken and residents began renting out their houses.