I despise John Brennan, Obama's choice for the CIA. The two American bloggers who have made the best case against him are Marcy Wheeler and Glenn Greenwald.
Regarding Chuck Hagel, I'm Hagelnostic. The other front runners, Michele Flournoy and Ash Carter, are both so inside of the borg, they can’t even see the box from where they are, let alone the outside of it. Reading some of their articles on defense policy last month was a good way to fall asleep. We're not going to get Dennis Kucinich as a Defense Secretary.
The battle over Hagel will essentially be a contest over how much influence the blindly pro-Israel neoconservatives will be able to openly enforce. This group works best behind the scenes, so an open C-SPAN-broadcast battle on the Senate floor against the confirmation of a former colleague would be unprecedented, and if they're stupid enough to try it, will most likely fail.
The best post-nomination roundup of reactions I've yet seen is by Philip Weiss, at Mondoweiss.