Personally, I think that the historical validity of Jesus’ Resurrection builds the strongest case for Him being the Son of God, and all the basic stuff that Christians believe.
Over at ilovephilosophy.com (philosophy forums) I’ve heard a couple of atheists, agnostics, or non-believers (as some I’m not sure what they are) say the same things:
1) The Gospels and New Testament letters were written too far away from the original events, meaning they cannot be trusted (and are probably mythological).
2) The disciples made the whole thing up so they could have a following of some sort (usually forms into some conspiracy theory of how the apostles were power hungry).
Of course, I’m summarising the general views.
Most of these seem to get their ‘facts’ from popular media rather than studying it for themselves. One person actually thought that Jesus died in 0 AD, and that is why they thought that since the earliest letter in the New Testament (Corinthians) was written in 54AD it was too long from the original event.
But Jesus was crucified 29-32 AD, which means that the letter to the Corinthians was written only something like 22 or 24 years after Jesus’ crucifixion and resurrection.
Why this is important is because Paul, in 1 Cor 15:6, claims that over 500 people saw the resurrected Jesus and that many of them were alive at the time of writing the letter. In other words, there were many people around to validate the event.
Myths don’t take 20 years to develop. Therefore only 20 or so years after Jesus’ death people believe He was raised again. Why didn’t the Jews produce a body or something?
When challenging an agnostic on the fact that they thought that Jesus was crucified in 0 AD I was told that ‘history cannot be verified’ and ‘historians argue all the time’. Only that I don’t think there is one historian in history, save perhaps David Ike (okay, not a historian, but you get my point) who says Jesus was crucified in 0 AD. So what real reason do they have to believe this?
The point is that i’m often told that the ‘historical evidence’ is laughable, but when I challenge this thought I’m told ‘oh, but all the historians argue about dates anyway.’ This is suspicious reasoning. If historical evidence is ‘laughable’ then it means the person is placing some stock in historical evidence (that which we do have). But, of course, because many actually haven’t really done any actual study on the subject they’ll eventually write it off to uncertainty, or keep speaking nonsense about how the Gospels were written in 120AD and Jesus crucified in year 0.
If you don’t believe that Jesus was actually risen from the dead in history then why do you believe that? Saying “history cannot be validated” is dubious, and going on about what some pseudo-historian said on Discovery Channel intellectually lazy.
If Jesus really was raised from the dead you are forced to take Him seriously as the Son of God. Ignoring the historical studies is convenient, but intellectually dishonest.
According to a bio I read of a guy called Gary Habermas, who lectures on the resurrection, he spent several years studying the subject before he realised that the resurrection of Jesus was a real historical event. He almost became a buddhist in this time, but was convinced when he studied the resurrection from a historical perspective (so he had no bias or reason to become a Christian). His site is very resourceful around this subject – see it at www.garyhabermas.com.
Life-Ecstatic 
The real miracle working Christ of the first century was Apollonius of Tyana. However, the Romans were not content with the iconic figure of their new religion just being Christ, which was a Hindoo and not Jewish concept which was brought back to Israel from India by Apollonius himself. They also wanted to usurp messianic title from the Jews. Much of this deals with the Balaam Prophesy and the Testament of Judah. This fact can be found in the writings of several Roman philosophers and authors of the day. “The balsam shrub is native to Judea but was brought to Rome by ‘the Vespasian emperors’ and it now serves [Rome] and pays tribute along with its race (cum sua gente) [i.e. Judeans]. The Jews did violence to it as also to their own lives, but the Romans protected it in response, and there has been warfare over a bush!”–Pliny the Elder. These horticultural analogies can also be found in the writings of Paul and Josephus. “For if thou wert cut out of the olive tree which is wild by nature, and wert grafted contrary to nature into a good olive tree: how much more shall these, which be the natural branches, be grafted into their own olive tree?”–Romans 11:24.
They apparently used these analogies in response to: “Then he will illumine the scepter of my kingdom, and from your root will arise the shoot, and through it will arise the rod of righteousness for the nations, to judge and to save all that call on the Lord.”–Testament of Judah 24.1-6. Suetonius sums up the whole matter: “There had spread over all the Orient an old an established belief that it was fated at that time for a man coming from Judaea to rule the world. This prediction, referring to the emperor of Rome, as it turned out, the Jews took to themselves, and they revolted accordingly.”–Suetonius, Vespasian 4.5
It was also Apollonius, Apollos of the epistles, who was the philosophical aspect of Paul. He along with his beloved disciple Damis and Lucius and maybe others penned both the original 9 epistles and the gospels for the Romans who were intent on subverting the religious beliefs of the Messianic Jewish Movement which was the fastest growing religon in the Empire at that time.
Quite revealing are the more secular mentions of Jesus Christ or Jesus of Nazareth. First, we have the infamous ‘Testimonium Flavianum’ of Josephus made at the end of ‘Jewish Antiquities,’ which was not published until the middle of the 90s, then we have the quotes by St. Ignatius of Antioch and Clement of Rome also made at the end of the first century and the beginning of the second century. At that time, we also have the famous apologetics quotes by Suetonius and Tacitus about Jesus and the Christiani.
Conversely, we have the Pauline Epistles which were written and preached during the 50s making no reference to Jesus of Nazareth. The author knows about a cosmic Christ the Savior, but nothing about a real live crucified Jesus Christ. Then we have ‘The Shepherd of Hermes’ which most scholars have attributed to the early second century, but others believe may have been written by ‘Paul.’ Paul was actually Apollonius of Tyana, who was of Greek ancestry, which makes him an obvous candidate to be the author. This scripture was a part of the early Church canon and makes no mention of Jesus of Nazareth. Then we have ‘The Epistle of Barnabas’ believed to have been written during the 80s. This early Church scripture only mentions Jesus Christ, but knows nothing about a real live flesh and blood Jesus of Nazareth.
The gospel accounts of the life and passion of Jesus Christ are believed to have been first written during the late 60s and early 70s. Strangely, prior to this time no one ever heard of Jesus Christ or Jesus of Nazareth. It was only after the gospels were written that we hear quotes about Jesus Christ. If Jesus Christ were a real person who was crucified c 30 CE we would not need gospels to tell us that he existed and that these events actually happened.
Dead Sea Scroll archivist Joseph Atwill in ‘Caesar’s Messiah’ clearly shows in the empty tomb narrative, which appears in all 4 gospels, that the gospels had a common source and were not eye witness accounts of some quasi-literate Jewish Apostles. Starting with John, then Matthew, then Mark and finally Luke, what we find is that in Matthew, Mary sees the tomb scene precisely as she left it in John and so on. This shows common knowledge among the authors of all 4 gospels. To learn more about how the Romans subverted the teachings of Yeshu and the Nazoreans and proclaimed them the revelations of their godman Jesus Christ visit: http://www. nazoreans.com