I place the fact that Jesus has saved my soul as the top 1 reason. However, the historical evidence for Jesus' existence is very strong, perhaps stronger than for any other figure in ancient history. The followers of Jesus wrote four historical biographies about Him. In addition, the book of Acts and the Epistles give us further information about what Jesus did, and about what the followers who were inspired by him did. On top of this, there are short mentions of Jesus in the works of the Jewish historian Josephus and other ancient historians.
I agree that Strobel's work is not academically rigorous. I usually recommend these two books:
Lord of Legend, by Greg Boyd and Paul Rhodes Eddy
The Historical Reliability of the Gospels, by Craig Blomberg