GMU economics professor Tyler Cowen is good on ethnic dining. He writes:
Here is the one file, print it all out version, just revised. Here is the blog version, which is easier to follow in bits and pieces, looks nicer, works better (thanks to the estimable Chug), and accepts comments. Here are the links on Twitter.
The old trends were good hamburgers and pizza. Those haven’t gone away, but the new area trends are Yemeni, Filipino, and more more more Chinese of many different kinds. Good Mexican is on the way, finally. Vietnamese and El Salvadoran are fine but stagnant. Persian is growing, Ethiopian is robust, and will more African be next? The biggest growth in quality and interest has come in DC (!), not the suburbs, at least this time around. In Virginia, Chantilly has made the largest gains.
The good news, at least from a culinary point of view, is that the gentrification of northern Virginia — northern and central Arlington excepted — is proceeding at a much slower rate than people might have expected say ten years ago.