Islam is important because it used to be a major way of life that leads to peace in yourself, between yourself and the surrounding people and universe, and between yourself and your Creator.
Islam is important because it the religion of nature. Islam is an Arabic word that means full submission to the Creator, Allah (God) and full submission to his will. All God creatures and all the inverse are fully submitted to God the Creator Except human kind as God left the choice for him. So, those who fully submitting to God the Creator are following the Doctrine of the Creator and hence are in compliance and in peace with the rule of Creation.
Islam is important because it is the mission of all prophets since the start of mankind, including Adam, Noah, Abraham (Ibrahim), Lut, Ishmael (Ismael), Isaac, Jacob, Joseph (Yusuf), Moses, David, Solomon, Jesus, and Muhammad. They all called for one message: There is no god except the one and only one God (Allah) the Creator.
Islam is important because it is last God (Allah) message to human kind that is concluding all previous God messages including that of Moses and Jesus.
Islam is important because it is based on last God (Allah) holy book to human kind, the Quran. See related question, listed below, on why Quran was revealed.
Islam is important because it was called for by the last God (Allah) prophet, Muhammad (PBUH) who was sent by God to humanity as the model for every aspect of life, State leader, good morals, leader in peace, leader in war, leader as husband, leader in conduct,...