4. Houston, TX
Population: 2,296,224. The populations is rapidly gaining on Chicago, actually, and may even surpass it in the next few years.
Nicknames: The Big Heart, H Town, Bayou City, and Space City.
Houston is a great place if you like heat, cowboy boots, and crazy Texans. Just kidding. The city is actually brimming with possibilities and has witness stable economic growth since 2008. The economy is diverse, and owning a home is not out of the question for middle-class families (unlike NYC or LA).
If you want an international experience, Houston is probably one of the best places for it, because there are over 90 languages spoken among the nearly 2.3 million residents. Yeehaw.