The story of David and Goliath is great. It teaches about courage and how the underdog can win with God's help. Also, the story of Jesus' birth, especially the visit of the three wise men, is very touching and full of hope.
The story of Noah's Ark is a popular one. It shows God's mercy and Noah's faith.
I'd recommend the story of Moses leading the Israelites out of Egypt. It's a powerful tale of liberation and God's intervention. Another good one is the parable of the Good Samaritan, which emphasizes kindness and compassion towards others.