The idea of civilization rebuilding with zombies is interesting. Imagine what would happen to the labor market flooded with cheap workers that neither have to be paid nor require those pesky healthcare benefits?
How about "Zombies on Mars" to aid the first settlers with construction of a dome city? If you're going for post-Apocalyptic, you could always use zombies for transporting goods across "hotspots".
Or of course you could go with the slightly absurd with oil supplies running out the world turns to putrid green power to solve their problems - Zombies. Whole rooms filled with them strapped to power generating machines. Wagons laden with goods being dragged across the interstates replacing semis. (Other than the stink, they're the ultimate in low emission power! Though, the drawbacks of having a car wreck where portions of the car are liable to get up and try to eat people might be a problem. Bah! Details!)