So far I've been doing cleanups in S. Louisiana, parts of Mississippi, and West Tennessee. My long-term project: fix Laredo, which is a mess in TIGER.
Just to update: I've fixed the line positioning in most of Laredo, but still need to do work on the area along S. Zapata Highway towards El Cenizo & Rio Bravo. I am also working on new subdivisions.
In terms of global OSM, I am starting to think about using TIGER 2007-08 addressing data to implement the Karlsruhe Schema for address geocoding. I think where the lines haven't been fiddled with too much the import should be fairly smooth once I work out some details (essentially: programmatically creating offset parallel ways to the existing ways for the address ranges). The programming shouldn't be hard, it's just lots of data (thousands of ways per county to create and associate with the right OSM ways).