Achievement 

Effective leadership is putting first things first. Effective management is discipline, carrying it out. (Stephen Covey)
The greatest gift in life is the ability to think great thoughts and have the strength to take action...While others simply dream. (Jack Black)
One person with courage makes a majority. (Andrew Jackson 7th US President)
If you think you can, you can. (Henry Ford)
We must all suffer from one of two pains: the pain of discipline or the pain of regret (Jim Rohn)
If you believe in what you are doing, then let nothing hold you up in your work. Much of the best work of the world has been done against seeming impossibilities. The thing is to get the work done. (Dale Carnegie)
Accomplish something every day of your life. (Walter Annenberg)

Purpose

There is no more noble occupation in the world than to assist another human being. (Alan Loy McGinnis)
Values are guiding devices to enhance our ability to achieve our purpose. (Allan Cox)
The purpose of life is a life with purpose (Robin Sharma)

Growth / Journeying 

Most great people have attained their greatest success just one step beyond their greatest failure. (Napoleon Hill)
Most people think of success and failure as opposites, but they are actually both products of the same process. (Roger von Oech)
Failures are finger posts on the road to achievement. (C S Lewis)
Happiness includes chiefly the idea of satisfaction after full honest effort. No one can possibly be satisfied and no one can be happy who feels that in some paramount affairs he failed to take up the challenge of life. (Arnold Bennett)
The most glorious moments in your life are not the so-called days of success, but rather those days when out of dejection and despair you feel rise in you a challenge to life, and the promise of future accomplishments. (Gustave Flaubert)
Obstacles are those frightful things you see when you take your eyes off the goal. (Henry Ford)

Happiness

Three grand essentials to happiness in this life are something to do, something to love, and something to hope for. (Joseph Addison)
The purpose of life is happiness. (His Holiness the Dalai Lama)
But what is happiness except the simple harmony between a man and the life he leads? (Albert Camus)
Are you bored with life? Then throw yourself into some work you believe in with all your heart, live for it, die for it, and you will find happiness that you had thought could never be yours. (Dale Carnegie)
Happiness is a continuation of happenings which are not resisted. (Deepak Chopra)
Happiness lies first of all in health. (George William Curtis)
Money has never made man happy, nor will it; there is nothing in its nature to produce happiness. The more of it one has the more one wants. (Benjamin Franklin)

Balance 

Most people struggle with life balance simply because they haven't paid the price to decide what is really important to them. (Stephen Covey)
One principle reason why men are so often useless is that they…divide and shift their attention among a multitude of objects and pursuits. (Nathaniel Emmons)
One by one the sands are flowing, One by one the moments fall; Some are coming, some are going; Do not strive to grasp them all. (Adelaide A. Proctor)

Authenticity 

No one saves us but ourselves. No one can and no one may. We ourselves must walk the path. (Buddha)
The best way you can predict your future is to create it. (Stephen Covey)
Motivation is a fire from within. If someone else tries to light that fire under you, chances are it will burn very briefly. (Stephen Covey)

Once you've found your own voice, the choice to expand your influence, to increase your contribution, is the choice to inspire others to find their voice. Inspire (from the Latin inspirare) means to breathe life into another. As we recognize, respect and create ways for others to give voice to all four parts of their nature--physically, mentally, emotionally/socially, spiritually--latent human genius, creativity, passion, talent and motivation are unleashed. (Stephen Covey)
The shoe that fits one person pinches another; there is no recipe for living that suits all cases. (Carl Jung)
It may be hard for an egg to turn into a bird: it would be a jolly sight harder for it to learn to fly while remaining an egg. We are like eggs at present. And you cannot go on indefinitely being just an ordinary, decent egg. We must be hatched or go bad. (C S Lewis)
It is the chiefest point of happiness that a man is willing to be what he is. (Desiderius Erasmus)