This seems like such a fundamental question. I am going to try to break down my feelings for Jesus Christ and why He is so valuable to me.
I have felt the consequences of my sin. There have been times when I recognize that I have acted against God's will resulting in the pain and harm of those I love. As I have prayed to know the right thing to do, I have been inspired to how to reconcile myself to God and to those I have offended. When I surrendered to those promptings and asked for forgiveness from the person(s) and from God, I have felt an immediate flood of relief and joy in my heart. It is especially potent when the other person frankly forgives me. It feels so good to be right with what I know God would want me to do.
From the Book of Mormon, the New Testament and elsewhere in the scriptures, I have learned about the fall of Adam and how sin came into the world. I see this life as a chance to choose between right and wrong with only faith and my conscience (or light from God) to guide me. As I have followed that light I have been filled with joy.
That light of God comes from Jesus Christ. He was chosen before the world was created to be our Savior. We all agreed to come from God's presence into this world, so we can grow to be more like our Heavenly Parents. From Jesus comes all Good. He created the earth. All the good you see in this world comes from Him.
Jesus lived a perfect life. He came to earth as the physical son of Mary and of Heavenly Father. Because of that he had power to lay down his life and to take it up again. Because he was the son of Mary, he was subject to the normal ills of life. He grew up as a normal child. Only he did not choose evil. Not even once.
At the end of his life he suffered for our sins. In a garden, he bled from every pore as he willingly allowed himself to feel the consequence of every sin ever committed. Not only sin, but every pain and heartache ever felt by any one on earth or that would ever be felt. He was able to withstand this because he is the Son of God. He was tested to the limits of his abilities. And He succeeded! In all this pain He never sinned. He died for our sins and then lifted himself up on the third day. He lives again! And because he did, every person will live again in a perfected body.
Why is Jesus so important to me? He is everything that is Good. He has blazed the path for me to be joined forever to that Good if I only will.