"The greatest achievement is selflessness.
The greatest worth is self-mastery.
The greatest quality is seeking to serve others.
The greatest precept is continual awareness.
The greatest medicine is the emptiness of everything.
The greatest action is not conforming with the worlds ways.
The greatest magic is transmuting the passions.
The greatest generosity is non-attachment.
The greatest goodness is a peaceful mind.
The greatest patience is humility.
The greatest effort is not concerned with results.
The greatest meditation is a mind that lets go.
The greatest wisdom is seeing through appearances." Atisha.
 "If you live the sacred and despise the ordinary, you are still bobbing in the ocean of delusion." Lin-Chi.
 "Aware of the suffering caused by the destruction of life, I vow to cultivate compassion and learn ways to protect lives of people, animals, plants, and minerals. I am determined not to kill, not to let others kill, and not to condone any killing in the world, in my thinking, and in my way of life.” Ven. Thich Nhat Hanh.
 "When the mind begins to become still, we then begin to truly see it. When you first try to stabilize and pacify the mind, initially it will become very busy because it’s not accustomed to being still. In fact, it doesn’t even necessarily want to become still, but it is essential to get a hold of the mind to recognize its nature. This practice is extremely important. ... Eventually you will find yourself in a state where your mind is clear and open all the time. It is just like when the clouds are removed from the sky and the sun can clearly be seen, shining all the time. This is coming close to the state of liberation, liberation from all traces of suffering. ... The truth of this practice is universal. It isn’t necessary to call it a religion to practice it. Whether one is a Hindu or a Moslem or a Christian or a Buddhist simply doesn’t matter. Anyone can practice this because this is the nature of the mind, the nature of everyone’s mind. If you can get a handle on your mind, and pacify it in this way, you will definitely experience these results, and you will see them in your daily life situation. There is no need to put this into any kind of category, any kind of "ism." Venerable Gyatrul Rinpoche

Is Buddhism a religion?
Whether Buddhism is or is not a religion depends upon how you define "religion." 

Government census offices and public opinion pollsters generally recognize Buddhism as a religion. Books that describe the religions of the world generally cover Buddhism along with Christianity, Islam, Hinduism, etc. Even the Boy Scouts of America, who expel Atheists, Agnostics and homosexuals, accept Buddhists as members.

The Drepung Loseling Institute states:

"Like all major religions, Buddhism contains an explanation of the origin of existence, a morality, and a specific set of rituals and behaviors. ... Buddhism presents a transformational goal, a desire to improve one's situation, and a distinct moral code. 5

However, some definitions of "religion" require a belief in the existence of one or more deities. That would disqualify most branches of Buddhism from being considered as religious groups.

Overview:
With about 365 milliion followers -- 6% of the world's population -- Buddhism is the fourth largest religion in the world. It is exceeded in numbers only by Christianity, Islam and Hinduism. Buddhism was founded in Northern India by the first known Buddha, Siddhartha Gautama. In the sixth century BCE, he attained enlightenment and assumed the title Lord Buddha (one who has awakened)

Buddhism later died out in India, but had become established in Sri Lanka. From there, it expanded across Asia, evolving into two or three main forms:

 Theravada Buddhism (sometimes called Southern Buddhism; occasionally spelled Therevada) "has been the dominant school of Buddhism in most of Southeast Asia since the thirteenth century, with the establishment of the monarchies in Thailand, Burma, Cambodia and Laos." 
 Mahayana Buddhism (sometimes called Northern Buddhism) is largely found in China, Japan, Korea, Tibet and Mongolia.
 Vajrayāna Buddhism  (a.k.a. Tantric Buddhism, Mantrayana, Tantrayana, Esoteric Buddhism, or True Words Sect). Some consider this to be a part of Mahayana Buddhism; others view it as a third Buddhist path.

To these might be added:

 Tibetan Buddhism. This developed largely in isolation from Theravada and Mahayana Buddhism because of the remoteness of Tibet.
 Zen Buddhism. This developed from within the Chinese Mahayana school known as Chan. Zen Buddhism is becoming increasingly popular in the West.

Since the late 19th century:

 Modern Buddhism has emerged as a truly international movement. It started as an attempt to produce a single form of Buddhism, without local accretions, that all Buddhists could embrace.