If you're a recent college grad looking for work, you might head to CollegeGrad.com for a start. If you do, you'll find the most posted openings for entry-level work are in New York (more than 3,600), then Houston (2,500), with Los Angeles and Boston ranking third and fourth for the quantity of job opportunities.
The list of the 25 cities with the highest number of jobs on the site is here.
Just remember that quantity of openings has little to do with quality of life. Entry-level work in New York City will often pay you enough for a shared apartment in Queens and a postcard to write home about it.