I agree that humility and a sense of oneself are very important in leadership. If someone tells me I'm being selfish, my response is, "who else is going to take care of me?" No one is going to hand me a sense of achievement, responsibility, or all the material things I could ask for. Its up to me to  achieve those things for myself, and I'll only succeed if I speak up or take action. This extends to the company I represent, and if i understand my own needs, then I'm going to understand my company's needs also... and that benefits more than just me. As a Mom, I have to take care of myself so that I'm able to be the parent my children need me to be.
While its important to realize the sense of oneself, its also important to note that 'oneself' encompasses ALL of you. Your wife is part of you, your company, your team, and your friends are all a part of you and therefore you become a better leader as you enrich their lives as well. That is why that even with a high sense of oneself, you can 'give more than you take' and you can make a difference for others.