I haven't really heard to much about the latest domestic migration trends and the overall health of our Metros, so I just thought I would put in my 2 cents on a few of our largest Metros starting from the top.
New York: City and suburbs still growing, although not booming. Exurbs seem to be growing the most (Hunterdon,nj-Monmough,nj-Ocean,nj-Dutchess,ny-Orange,ny), City center is Vibrant as well certain parts of the outer boroughs. Alot of flight overall to the Southern U.S. and Arizona/Nevada.
Los Angeles: Large domestic flight, right out of the state. Lots of Intl migration to more than make up for the losses. Some of the domestic die-hards are moving to far out exurbs (Rancho Cucamonga, Palmdale, Southern Orange County and Ventura County.) Being the center of the entertainment industry and its position as a major global gateway will keep this Metro vibrant despit major domestic losses.
Chicago: Large exodus, although alot of nearby Midwestern population flow into it along with internation migration are helping keep this metro floating right along. City center is very vibrant with alot of young professionals coming in. Most growth in the exurbs (Will, McHenry counties)
Washington/Baltimore: Probably the largest Metro which is receiving a net increase in domestic as well as a large influx of international migration. City center as well as suburbs and exurbs are booming, but esp the exurbs.
San Francisco Bay Area: Big time exodus, although the city of San Francisco is definitely holding its own. Large and Wealthy internation in migration is keeping this Metro from declining. Some exurban areas growing(Northern Solano and Eastern Contra Costa counties.
Philadelphia: Small exodus, but vibrant city center is still attracting young professionals and Baby boomers. Suburbs still growing well. Phili is unique to me because I really haven't heard about a huge Exurb boom. I guess Northern Bucks and far Western Montgomery are growing pretty well but in no comparison the exurbs in other cities.
Dallas Metroplex: Booming all the way around, positive numbers in both domestic and intl migration. Again not heard to much about this Metros exurbs, unless you consider Plano and exurb, in that case their booming.
Boston: Small exodus, Intl migration and being a large magnant for young professionals help keep this Metro doing well. Investing wisely in it's inner suburbs, although Southern New Hampshire would definitely qualify as booming exurbs.

Iiat,

Interesting observations. I believe that you have hit upon one of the key points in urban revival.

Most of our older US cities (particularly in the east and midwest) suffered after WWII do to suburbanization. Sun Belt cities, of course, grew during that time.

There are a number of factors that drew some cities out of their decline. One of the most important: immigration. In major business and cultural centers, it was immigration that not only reversed the trend toward population decline, but also the trend to revigorate inner city neighborhoods. We hardly give enough credit to the drive, the energy, the desire to make things better for their children that immigrants bring with them to America. Immigrants have added a new vibrancy to cities who, without them, wold have continued to decline.

Unfortunately, due to the need to have sufficent sized immigrant communities and the opportunities that major cities offer, the trend has had far greater effect on first tier cities than on smaller ones.