Recovery.gov is off to a good start. Good design. Nice visuals. Early opportunity for citizen engagement. (Others think so too.) But I'd like to be the boring person here in the transparency community and say: keep your eye on the ball. For the site to be successful it has to get the fundamentals right -- transparency for the data it will house.
The basics are pretty simple. Recovery.gov must make the raw data available and it must be housed in system so that data can flow in and out easily. There should be open programming interfaces that allow developers to share and analyze data. Timeliness is key, so is accuracy. That, plus a few simple tools for easy citizen access would be a great place to start.
A little blogging now might help with a few of the basics: What data is getting collected and how often? Who has to report? How often will the data be updated and how often will it made available to the public? What's the database going to look like what's the relationship to USASpending.gov? What kinds of content will Recovery.gov produce around the data? (Will there be regular emails when new information is available, blogging with analysis, etc.)?
The Coalition for an Accountable Recovery has some additional ideas.