Many of the goals of data.gov will only be realized when many govt data shops serve web services using common standards so they can be accessed by other web services and synthesizing portals. Like a common 'what data exists in your database in this ___ geographic area [lat long box, county, zipcode, LL/zip centroid plus distance]?' web service standard. Work with teams in the major gov data centers to develop standards and offer incentives to follow those standards so they will be used and then the true synergy of diverse data is then possible. Airlines, hotels, and car rentals, have done this so that you can use the portal of your choice [kayak, expedia, etc] to find the flights you want.