This trend (moving back into city centres) has been around for a long time, and is well documented. The USA is slower than most of Europe on this (although they generally did not desert the city centre quite so much). Its worth also noting that a lot of this is down to government and planning laws, which in the 1950s (generally when they were introduced on a wide scale) hugely subsidised suburban development and road…
http://en.wikipedia.org/wiki/White_flight
Another part of the governmental subsidy problem is that governments by design tend to redistribute wealth out of cities and into rural and suburban areas. It even happens at multiple scales; Seattle pays taxes to the Washington State government which are then redistributed to outlying towns, but Washington pays taxes to the US federal government which are then redistributed to Wyoming and Alaska. Until governments are redesigned along the principle that human beings, and not parcels of land, are the true stakeholders, this will be a systemic problem.