Quantum of Solace.  Sounds like someone borrowed the George Lucas Random Movie Name Generator again.  Quantum of Solace makes no sense.  A quantum is a discrete amount of something, certainly not solace. Can solace be even measured at all? 

So who thought of this title?

Surprisingly, Ian Fleming. It's actually a short story written by Fleming that has James Bond, but no action and where he's not even the main character.  Wikipedia has a brief summary of the story. James Bond movie plots (an oxymoron?) sometimes have little to do with the the story in which the movie name was taken.