Bond was constantly thinking of Vesper, as several characters pointed out numerous times throughout the film. He just didn't go on about it. It was internalized and behind the eyes -except when he was killing people, which he seemed to relish until the climax.
At the end, he chooses the mission over revenge, squeezes Greene and leaves him to Quantum. When he doesn't kill the boyfriend, it's because he learned from Camille that the revenge he was seeking didn't actually bring closure or make things better. He killed bag-fulls of men in anger and it didn't make the pain go away. She had to find a new purpose and move on (helping with the rebuilding of Bolivia, redistributing the water supplies, etc). Bond decides to do the same and get back to the job of saving the world (which, incidently, will involve killing many more bag-fulls of men).
I thought it was a great counter-point to CR and really enjoyed it.
As an aside, anyone else notice that Marcus, the head vampire from the Blade series had a very brief, violent, knifey role as Slate? Must have been one of those "I'll play a stormtrooper if you just let me be in this movie" roles for him.