I just started reading XP explained by Kent Beck. I read through the 'Values' of XP chapter and was really inspired. It made a lot of sense to put such a chapter in a book. It somehow takes things beyond the usual tricks and tips. It sort of gives you a feel of what should drive things. Among the important values mentioned (communication, simplicity, feedback, courage and respect), I felt the last two were pretty important ones. I felt that the most important thing for a team to win (whether they follow XP or not) is mutual respect for each other. While respect out of politeness is a nice thing to have, I feel the real respect would come if each member knows the other as equally competent as her/him.
Another thing which was mentioned in passing in the book, is conceptual integrity. When Kent talks about the team moving towards a common coding style that is what he seems to be hinting at. I have always felt it to be an important thing.
But then, he himself raises the question of creative independence - something which will have to be foregone to achieve conceptual integrity. What should one chose?