Swopa over on Needlenose brings up an important point: the name of the game in DC journalism is be kind to your sources.
Many journalists in Washington may be uncomfortable with the Plame Affair because it is so close to the heart of what it is they do every day: build relationships with insiders who will give them the hot scoops they will need to keep their top-level careers viable. A leak scandal threatens the very core of DC journalism because it might lead to those valuable wells drying up.
Swopa also points out that the reason why Mike Allen, Dana Priest and Walter Pincus have owned this story may simply be because they are the only ones with the sources who have something to gain by getting this story on the front page.
In other words, even the journalistic "good guys" are in it primarily for their own benefit.