Jesus was God manifested in the flesh just as it says in 1Tim 3:16 He is the savior of the world [or rather the part of the "world" that does not reject Him]
I think the historical testimonies of the apostles and other witnesses is sufficient evidence of His crucifixtion and resurrection three days later. I mean, logically, there HAS to be a God - it's illogical to think otherwise when you consider the extremely intrinsic interrelated systems in cell compostions, laws of nature, reproduction, etc. However, that is NOT what brought me to my belief in Christ. I came to him kicking and dragging and screaming and didn't believe a darn thing until I saw the PROOF in my life. I started my prayers this way for 3 years [out of desperation]: "If there really is a God up there....." After about 3 years of doing that one day I was trying to explain to someone why my entire personality, level of intelligence, likes/dislikes and appearance had dramatically changed, and it struck me while I was trying to explain this that it was not possible for me to implement such changes through the force of my sheer will. This knowledge struck me speechless because I could no longer doubt his existence. It was impossible. I KNEW.
And if you are thinking that I came to my belief in a somewhat emotional fashion, you would be right - because anything beyond that would have been impossible for me - I was an emotional thinker who had no logical capabilities.
From a self-employed writer...
I am a Christian; I believe Christ was the Son of God. I know God exists (through personal revelation); my faith in Christ is the result of study of various world religions, choosing the one which held up to my arguments time after time.
The historical data about Jesus is pretty patchy, but 4 seperate accounts remain of his life and resurrection... that's a lot, all things considered. The rational arguments of CS Lewis and Madeline L'Engle did a lot for me; so did a friend of mine, who "witnessed" by his life. One of the things I found, when I was first forced to read the Bible in a college class about comparative world religions, is that Jesus was a cool guy... someone with a sense of humor, someone I would really enjoy being in the same room with and talking with. Non-Christians are very fond of depicting Jesus as humorless, prudish and stern. For me, actually researching the Bible and the people who wrote it, when I was not a Christian, was what first lured me into Christianity.
From an electrician...
Jesus Christ is Almighty God, the "second" person of the Trinity. Coequal and Coeternal with God the Father. He is also my Lord and Savior. It is only because of His blood, shed at His death on the cross, that I have eternal salvation.
The Bible (especially the New Testament). If we cannot accept the report of the eyewitnesses, who can we believe? The Bible gives me no reason to doubt its accuracy. Nothing archaeologically ever invalidated it. In fact, when opportunities arise to put the Bible to an objective test, it passes with flying colors.
It is backed up historically. (Old Testament accounts of kingdoms, wars, geography, etc; New Testament accounts of 1st Century life in Israel and Asia Minor, cities, Roman politics, Greek culture, etc.)
It speaks the truth about the human condition. No stories about 'George Washington never telling a lie,' here. We learn about the greatness and the adultery of King David. We see the wisdom and the idolatry of King Solomon. We Paul losing his temper, Peter betraying his Lord, and Thomas having his doubts.
It is more reasonable than the alternative. C'mon, a big "bang?" Caused by what? In an atheistic universe, all there is, was, and ever will be are natural laws. The problem, however, is that natural law is the result of the existence of the universe. Before the "bang," there was no universe, and hence no natural law. But if the natural law is needed to cause the big bang didn't exist, why then are we all here talking about it today? As I said the Bible is more reasonable.
Need I say more?
Most of the eyewitness were martyrs. That is they died for claiming that Jesus Christ is God, and that He did rise from the dead. These men spent three years with Jesus before the crucifixion. It is reasonable to conclude that if Jesus did not perform the miracles and healings, or make the claims about Himself ("before Abraham was, I am") and predictions about His coming resurrection ("destroy this temple, and I will raise it up in three days"), they would have known. Furthermore participants in a resurrection hoax are not likely to die for it. I conclude then, that they indeed saw the miracles, heard the teaching, and were witnessed of the resurrected Christ; and they were not afraid to say so, though it meant their deaths.
"Cogite, ergo sum" is still a pretty good argument, in my opinion. If the soul exists, then it is not because of natural law. The law of conservation of mass/energy tells us that we are NOT greater than the sum of our parts. Non thinking pieces (atoms, molecules, etc) do not combine to form a self aware, thinking whole. Since the universe had a beginning, and time is a property of the universe, then time had a beginning. Since the universe cannot create itself (nothing is there!), then someone must have created it. This person existed "before" time (time didn't exist before there was a universe), and is, therefore, eternal. If we (our souls) are not created by natural law, it follows that someone outside nature (time and creation) created us, and that person therefore is eternal. If we exist, then, it is because God existed before us, and caused us.