I cannot think of a word that describes the feeling of "doing the right thing". I.e. the feeling as a result of having made the right choices, of committing an act of altruism, of having made the correct decision. It needs to describe the feeling — there are lots of words for the act itself.
EDIT: Great feedback thanks. None are quite hitting it on the head so I'll go further and say that the word needs to imply no selfish motivation - the act of "doing the right thing" is implicitly done for the greater good, rather than to satisfy their own ends.
I guess the philosophical arguments about whether anything is ever truly done for non-selfish reasons will need to wait ;)