I'm not convinced that Jesus ever existed.
Now, some people say that, and what they mean is: sure, there was a Jesus who inspired the stories in the New Testament, but I'm not sure that all of those miracles actually happened. That's not what I mean. I don't believe any of the miracles described in the New Testament happened, and I don't feel that that is worth debating, any more than it would make sense to debate the existence of Santa Claus or the Easter Bunny. What I mean is, I'm not convinced that there even was a completely non-supernatural person named Jesus, or even with another name, who preached in Galilee and Judea and was crucified on Pilate's orders, or even wasn't actually crucified, and inspired the stories in the New Testament. So much of the New Testament was invented, the descent of Jesus from David, the virgin birth, the star of Bethlehem, the slaughter of the innocents, walking on water, water into wine, rising from the dead, etc, etc, etc, that it seems quite reasonable to me to wonder whether Jesus' non-supernatural existence isn't just one more fictive detail.
It also seems to me that many Biblical scholars, including seemingly most of the most prominent ones in the US, react quite unreasonably to any doubts about Jesus' existence. Perhaps the most notable example in the past few years is the normally quite reasonable Bart Ehrman's book Did Jesus Exist? -- a more accurate title for which would've been the last three words in the book, Jesus Certainly Existed, with a couple of rude insults to all who are not certain in the subtitle.
Rude but unfortunately not untypical. Refusing to acknowledge that reasonable people -- lots of them -- have doubts about Jesus' existence does not encourage those reasonable people to study the scholarship of the professionals has driven many of them into the arms of amateur self-appointed experts. (I, of course, am completely different from all the other amateurs. Harrummph. All of them. Yeah, that's the ticket!) With the predictable result that the level of discourse about the historicity of Jesus is pretty abysmal. I (harrummph) am doing what I can to help.
You will often hear the assertion that there is no evidence that Jesus existed. This involves a drastic misunderstanding of the term "evidence." Evidence is not the same as conclusive proof. Evidence can be strong or weak, conclusive or inconclusive, strong or absurd. The New Testament is the primary evidence of the existence of Jesus. If the New Testament by itself doesn't convince me that Jesus existed, that's fine with me, it hasn't convinced me either. But if you discuss Jesus' existence without considering what the New Testament has to say, you're ignoring most of the pertinent information having to do with what you're (allegedly) talking about. Knock it off. If you want to take part in this discussion, study the New Testament in depth. If you don't you're a silly person and you should go away.
While I'm here: in these discussions, you'll often hear the assertion that apart from the New Testament, no 1st-century writers mention Jesus at all. That's almost correct: Josephus mentions Jesus, but just barely, in a passage which is mostly about James, known as the brother of Jesus. (The other passage, in which Josephus praises Jesus at length, is a fake.) The thing is, though, other than the New Testament authors, Josephus and Philo, no one whose work we now possess says anything about Gelilee or Judea during Jesus' alleged lifetime at all. So, no, we do not have reams and reams of descriptions of the time and place in which all mention of Jesus is suspiciously absent.