Governments have agendas, media outlets have agendas, Assange may well have an agenda... Sure. But at least he adds a new agenda to the mix in that case, because I'm about sick of having only the gov't & established media agendas to choose from.
Wikileaks (which is not only Assange, after all) is at least an interesting addition to the 'fourth estate' role the media is said to occupy... And the media choosing what to print and what not to? That's hardly anything new, is it?
[added] Oh, and apparently OpenLeaks is the next competing site, to be founded by a former WikiLeaks collaborator. So, probably whatever agenda they may or may not have, it'd be similar to Assange's outfit.