The Four Noble Truths encompass the basis for all Buddhist thought. They are heavily stressed in the Theravada or Hinayana school (one of the three Buddhist divisions), and are key to understanding the meaning of enlightenment. Buddhists do not believe in a permanent self identity - meaning liberation from the world (Nirvana), would result in a state of non-being. In order to reach this state, Buddhists concentrate on meditation to break the cycle of re-birth. By stopping the process of re-birth, one can obtain immortality through enlightenment.
The Five Khandhas represent five traits that are not permanent. Wanting permanence leads to Dukkha (suffering).
It is important not to confuse the term "Buddha" with "God." In the West, Buddha is mistakenly referred to as a god. While Buddhism does not deny the existence of any deities, it does not elaborate on a specific "supreme creator."
The term "Buddha" can also imply a teacher of Buddhism, or one in general who is currently seeking the path to enlightment. It is also commonly used to refer to statues and other pieces of art, but again - should not be confused with the concept of "God."
By following the Eight Fold path, a Buddhist hopes to gain enlightenment through Nirvana. Through Nirvana, they will ultimately reach immortality. There are two types of Nirvana: sopahisesa (with remnant) and nirupadhisesa (without remnant). Sopahisesa refers to Nirvana in the living world, while nirupadhisesa refers to Nirvana after death.
The Five Precepts are the basis for all Buddhist teaching. They are stressed, but not enforced. It is up to the individual, and only the individual alone, to decide whether or not to follow the precepts.