Check it out: Big salaries for Washington lobbyists

PhRMA's Billy Tauzin; the late Gene Upshaw of the NFL Players Association; Dan Glickman, formerly of the Motion Picture Association of America. (Mike Wintroath/AP; Chip Somodevilla/Reuters; Ethan Miller/Getty Images)

The best-kept secrets in Washington aren't about sex, they're about salary. Which is why the annual compensation for lobbyists and interest groups -- detailed in the new issue of National Journal, primarily from 2008 filings -- is so intriguing.

Topping the list: Business Roundtable's John Castellani, who pulled in $4,373,723, followed by U.S. Chamber of Commerce head Tom Donohue with $3,731,380.

Former congressmen did very well for themselves: Pharmaceutical Research and Manufacturers of America paid outgoing head Billy Tauzin $2,907,732; Dan Glickman made $1,343,532 while at the Motion Picture Association of America; and Steve Largent got $1,173,298 from the Wireless Association.

Think tanks can't compete with big business: Aspen Institute's Walter Isaacson made $705,711, while Brookings Institution paid Strobe Talbott $412,500.

Worth noting: The NFL Players Association paid the late Eugene Upshaw $2,397,339. And Bobby Koch, brother-in-law of George W. Bush, made $1,100,000 from the Wine Institute.