First off, I'm not an Atheist. I was raised a Catholic, although I don't believe in everything that Catholics do and have my doubts on certain things (for example, I don't believe in the Old Testament and am skeptical of the New Testament). I always held the belief of Eva Strautt of Project Mary....I choose to believe in God "because it beats the alternative." I do believe there is a God...I don't know whether he had a divine son, Jesus, though.
I also am a History major and have studied this subject of Jesus ad nauseum, reading basically what every historian has said on the subject. I really like the podcast "The Rest is History" and Tom and Dom's take on this subject. I basically re-iterate a lot of what they clam.
That said, in terms of Jesus. I've read enough historians' take on this to firmly believe that Jesus really did exist. There was a rabbi named Jesus who had a following that grew over time some 2,000 years ago. He had a close group called apostles. He had a cousin, John the Baptizer, and I believe many of the things John said and did, along with his execution, were true.
Jesus was very popular. He helped people...now, whether he did actual miracles can be debated. That's a question of faith. But one could say he was "a doctor" who helped people. He went into Jerusalem for the Passover, claiming to be the Son of God. He was a "strange figure who spoke in parables and puzzles. The Sanhedrin saw him as a serious threat, arrested him, had a trial, turned him over to Pilate, who had him crucified. His apostles spread his message, and Christianity evolved from there. But I believe much of the Passion story from Holy Thursday to Good Friday is 100% true.
Now, in terms of whether he truly resurrected from the dead, raised Lazarus, was seen by people after his resurrection, performed miracles, and ascended into heaven...in other words, the supernatural...that's a question of your faith. I'm not going to knock anyone for their beliefs one way or another. You believe what you believe. Yeah, I think the Shroud of Turin is real, but it only means that Jesus existed...it's not evidence he was raised from the dead.
People say, "Where's the evidence?" Well, we do have some evidence. We do have some writers mentioning his name. And I'm not going to discount these four gospel writers as complete hacks who fictionalized the whole thing. Why would they make up some of this stuff? For example, why would they say he was from Nazareth? Wouldn't you say Jerusalem or somewhere more popular? I just believe this stuff wasn't completely fabricated. The fact the four writers do differ on their stories is also proof to me because if this was completely fabricated, they would have gotten together to make sure the facts were true. I believe there's a lot of truth to what happened with Jesus...just maybe not 100%. Like I said it's a question of faith. But I do believe that Jesus really did exist and was crucified to death.