For years, one of the most popular and oft-related memes around here has been about the in-migration of southern Californians to the Inland Northwest (and how they're ruining everything). You hear these kinds of anecdotes everywhere. People are leaving Detroit en masse. Seems like everybody's moving to Portland these days.
Forbes.com has a cool map that actually shows some of this stuff, though. The map, which you can find here (or by clicking the image below) uses IRS data to track people who moved from one county to another in 2008. Click on a bigger county and you'll see what looks like a meteor blast — red lines are moves of ten people or more out of that county, and black lines are moves of ten people or more into that county.
The map gives a couple suggestions at the bottom, including Manhattan (which shows a pretty even mix of inward and outward movement) and Detroit (where, indeed, everybody's getting the hell out).
But poke around for yourself. Spokane County shows a lot of people moving east of the Mississippi. The map seems to back up the notion that new Kootenai County citizens are coming from SoCal. And, holy smokes, look at Portland's Multnomah County: Everybody wanted to be there in 2008.