Bay Area/Silicon Valley, California: As home to the world’s highest per-capita population of tech startups and web-based companies, Northern California is not only a popular place to find jobs, but it is also steadily becoming a very expensive place to live. Thanks to area residents like Facebook and Twitter (just to name a couple), Silicon Valley and neighboring San Francisco Bay have some of the highest costs of living in the nation, but one can’t deny the high number of employment opportunities in the region. Cities like San Jose – where 22-to 35-year-olds are averaging yearly income of $79,000 – are major draws.