Buddhists have several cardinal beliefs just as all other religions do... they have sets of rules, principles, moral code and specific goals in life to live by which are the basic concepts taught by Buddha Himself. The most coveted and important beliefs they stand for are the 4 Noble Truths, the Noble 8 Fold Path, Karma, and Reincarnation.
Karma
Karma is a word that literally means "action". The word is used to refer to acts as well as the consequences that arise from these acts. The idea of karma had existed in ancient Indian philosophy before the time of Siddhartha Gautama, and it became an important element of Buddhist philosophy.
Reincarnation
Rebirth has always been important in Buddhism; and it is often referred to as walking the wheel of life (samsara). It is the process of being born over and over again in different times and different situations, possibly for many thousand times.
The Noble 8 Fold Path
In Buddhism, it is believed that one can escape from the vicious cycle of birth and death by following the noble eightfold path, listed on the bottom of the page.
The 4 Noble Truths
They were formulated by the Buddha Gautama in his first sermon. The way to accomplish this is to follow the Eightfold Path. Though differently interpreted, these four truths are recognized by virtually all Buddhist schools. Listed on bottom of page.
Karma and Reincarnations Info from:
4 Noble Truths info found on Answers.com