as a muslim, I believe Eesa (Jesus) was a prophet of god, and I don't believe any 100% reliable account of his life exists.
I don't believe human beings need a saviour because for thousands of years there were righteous human beings walking the earth - so they were doomed to either hell, or someplace in between just because Jesus wasn't born yet to save them?
Is abraham in heaven? Is moses in heaven? well I didn't see any of them praying to a "jesus" - and I didn't see them waiting anytime soon for god to be born as a man and die...especially since in the old testament, god came to earth anyway to wrestle one of the prophets in a wrestling match ( yes I do have a reference if requested ) - if he needed to be sacrificed they could have just done it then.
Humans are naturally sinful, and regardless of whether or not you "accept" jesus as your "saviour" - you're the same person before and after your conversion.
check out
www.jewsforjudaism.org - this is why i don't believe in jesus christ as my saviour.