I'm reading a book and this morning I got to a part where it claimed that the life of Jesus was very similar, if no downright copied on ancient pagan myths of different men-gods. (Amongst them Osiris, Dionysos, Attis, Adonis, Bacchus and Mithra.)
The problem with these so called "copied" "parallels" is that:
1. They frequently are really non-parallel and only become seemingly "parallel" by the use of equivocation in terminiology (such as defining death by an arrow as "crucifixion", etc.).
2. The frequent use of post-christian pagan sources.
3. The use of completely unsubstantied/undocumented claims.
4. The fallacy that similarities must have come from dependance.
5. Ignoring or dismissing (without valid merit) the substantial historical evidence for the existence and life of Jesus Christ (for example the crucifixion under Pilate is documented in several extra-bibilcal and secular sources as well as multiple biblical authors.).
http://www.tektonics.org/copycat/copycathub.html
http://www.answersingenesis.org/home/area/faq/Jesuschrist.asp