This Sunday Chronicle article has the nice graphic on the left that puts into perspective the size of the new Wal-Mart Distribution Center in the Cedar Crossing Business Center near Baytown between Houston and Beaumont by comparing it to other large facilities in the Houston area.
By the way, Tory Gattis over at the smart Houston Strategies blog provides this nice analysis of the probable economic impact of the Wal-Mart Distribution Center on the Houston area economy. In particular, Tory notes the following:

It’s an important part of Houston’s economic diversification to offer quality blue-collar jobs outside of the oil industry. One of the things I’ve always liked about Houston is our mixed white/blue-collar economic base, which I think makes for a more diverse and interesting city.

On a related note, this Houston Business Journal article points out that Wal-Mart received $19 million in infrastructure improvements and property tax exemptions for the Wal-Mart Distribution Center in Baytown, which was the fifth largest of over $1 billion in such subsidies that Wal-Mart has received from various governmental entities to induce the company to build facilities around the country.