I haven’t read every post on this thread so this may have been covered (never stopped any of us, right?):
As far as the pagan origins of Christ, I don’t think there’s much doubt that ALL religions cannibalize previous traditions so it’s not a great leap to say the Christ myth was probably derived from Egyptian, Greek, Persian and other pantheons just as these older civilizations built on prehistoric belief systems and so on. There’s no reason to have to pick apart every sentence of the Jesus narrative looking for evidence — although it can be fascinating as a practice of mythology.
There are many examples of rising and dying gods that were very popular throughout the Near Eastern world and, at the very least, we can say there was a correlation among them if not, at most, a direct/indirect causation (Mithras begat Dionysius begat Jesus — or whatever the sequence).
What this tells us is there were certain philosophical memes in the air during those years — cultural trends, if you will. Despite their lack of reality, they obviously fulfilled some sort of cultural or emotional need by the people of that time period who were in the midst of tremendous historical upheaval (changes in commerce — goods AND ideas, changes in empire, cross-cultural mingling, etc.)
So, to me there is no real debate about pagan roots in Christianity (call it Horus or Mithras or whatever) — it’s obviously present as it is with all world religions (Hinduism birthing Buddhism, etc.)
Think of a modern example: Many people obviously have some kind of cultural need that is fulfilled by watching competitive “reality” shows. So, shows like Big Brother develop and, later, similar shows, like American Idol and Dancing With the Stars evolve from the same need-driven concept or meme. Only, in our society, these cultural memes catch on much more quickly thanks to instant, worldwide communication. Ancient religion evolved much slower and was gradually filtered through various cultural beliefs (like Christianity was filtered through Judaism).
Now, as to the evidence of a historical Jesus, my own amateur investigation leads me to conclude that there probably were one or more Jewish prophetic figures who were blended together to form the modern Jesus image (as well as John the Baptist) — the same goes for the Buddha, King Arthur, Hercules, etc. I mean, look how quickly American mythologized George Washington and the “cherry tree.” We human love to take regular folks and stretch them into legends. For better or worse, the Jesus myth took off at a time when monolithic philosophical thought was highly contagious as was migration.
OK, I will now shut up, safe in the knowledge that my words and avatar will someday spark a new “religion.” Mountanas Humanasis?