Bond wants to find the people responsible for Vespers death, he is not doing it FOR Vesper, He's doing it for himself to find his quantum of solace. Of course, Vesper is on Bonds mind. But revenge takes a back seat in this. Everyone else thinks he's gone off the rails and is killing every possible lead because he feels like it.... which is not true.
Sorry for this rant, it's just that the reviews have annoyed me when they say that Bond has turned into a charmless killing machine. Some of them don't realise that the situation he is in causes him to react how he does.
Enjoy the movie on friday.