Originally posted by FabianFnas
Nirvana and reincarnation are important phenomena in Buddhism, they are supernatural, therefore Buddhism is a religion.
It would seem that not all Buddhists agree on that.
"What Reincarnation is Not
Reincarnation is not a simple physical birth of a person; for instance, John being reborn as a cat in the next life. In this case John possesses an immortal soul which transforms to the form of a cat after his death. This cycle is repeated over and over again. Or if he is lucky, he will be reborn as a human being. This notion of the transmigration of the soul definitely does not exist in Buddhism."
http://www.buddhanet.net/e-learning/reincarnation.htm
Speaking of what all Buddhists presumably have in common, "Although Buddhism has a vast number of scriptures and practices, the fundamental core of Buddhism, the Four Noble Truths and the Noble Eightfold Path, are distinguished in the world of religion for not having any mention of God(s) or any notion of worship of any deity. They are purely ethical and meditative guidelines based on the truths of psychological suffering due to impermanence" (http://en.wikipedia.org/wiki/Nontheism#Buddhism).
So it seems that according to your definition, Buddhism might or might not be a religion, depending on the individual practitioner.