Judicial Watch is a public interest group that investigates and prosecutes government corruption. It recently released its list of the ten most corrupt politicians of 2009. After reading the list I'd say they pretty well nailed the top ten quite accurately. Of course of the 535 members of the House of Representatives and the Senate, it would probably be a lot tougher to name ten politicians that weren't corrupt.
Regardless, the "honorees" making the most recent list in alphabetical order are:
1. Senator Chris Dodd
2. Senator John Ensign
3. Representative Barney Frank
4. Secretary of the Treasury Timothy Geithner
5. Attorney General Eric Holder
6. Representative Jesse Jackson Junior/Senator Roland Burris
7. President Barack Obama
8. Speaker of the House Nancy Pelosi
9. Representative John Murtha
10. Representative Charlie Rangel
See the link here for the specifics of why Judicial Watch placed these stellar examples of public servants on their top ten most corrupt politicians list.