The Census Bureau is out with its latest population estimates through July 2012, which lets us see which states have seen the most rapid population growth between July 2011 and July 2012. The winner is economically booming North Dakota. North Dakota is so small that it could only plausibly absorb a tiny fraction of currently jobless Americans, but the unemployment rate there is super-low so its smart of people who are open to relocating to give it a look.
Following North Dakota is Washington, DC which is seeing a somewhat smaller rate of people migrating here but a somewhat higher birthrate. Unlike DC and ND, Texas already has a huge population so its continued rapid growth is much more quantitatively significant. Texas growth is nicely balanced between in-migration and natural increase.