I have not been a big fan of the superficial, fluffy, morally-ambiguous Avengers movies. I am a huge comics fan, but it seems to me that Marvel Studios hasn't had nearly enough guts to take the series as dark as its origins. If this news turns out to be true, though, my opinion of them will go up far higher.
According to the Hollywood Reporter (see here), James Gunn is now the frontrunner for the job of directing Guardians of the Galaxy, an Avengers spin-off taking place in space. Gunn was the director of Slither and Super, the latter of which is my favorite super-hero parody film of all time. Gunn is known for a twisted by very funny sense of humor and skillfully merging action, comedy, and drama. His R-rated style is not what one would first expect for a Marvel Studios movie, but I think it is definitely what the franchise needs it.
The other names that are out there are Peyton Reed (Bring it On, Yes Man) and Anna Boden & Ryan Fleck (Half Nelson, It's Kind of a Funny Story). I am not familiar with Reed's work, but I am a fan of Boden & Fleck's and would be excited to see their take on a comics story. According to this article, though, Gunn is the current favorite.