I would rather side with the "just a man" opinion, even if I can't claim that I am absolutely certain about it. I believe that he was extremely charismatic man, understood concepts in away to far too advanced for his times, but still just a man.
And for that reason those who were creating a religion based on his teaching, modified the story and his teaching, so they would fit their beliefs and the beliefs of people of that time and could be accepted by them, divine nature was one of those modifications. I also believe that by "playing God", they (the founders of the Christian church) destroyed 9/10 of the message that Jesus wanted to pass to the people.
Now, I don’t think that Jesus went to India (even if, who knows?), but I do believe that his relationship with Maria Magdalena was intimate, although not necessarily carnal and even if it was carnal, I don’t find anything wrong with that. What is wrong about love a woman or having a child from her? In the matter of fact I don’t find anything wrong with that even in the case he is the Lord. I don’t know why Christians go so mad about it.
Referring to “Da Vinci Code”, I find Brown approaches in a too superficial way, matters that are too serious and use them as a background for his story. But the good thing is that it became so popular. It is a good point to make people start asking questions, but for any information on the concept that this book touches I would suggest the documents of the Apocrypha and Pseudepigrapha. They vote strictly for the “Lord-option”, but give a much more interesting perspective of the matter than the texts that are recognized by the church.
http://www.pseudepigrapha.com/ might be useful.