Tacitus was supposedly born after the "christos" he writes about, so it would not be accurate to say his writing is a first hand account.The writings of Josephus the Jewish Historian gives a brief account about Jesus There is also the writings of Tacitus,Thallus, Philopon, Lucian of Samosata, Mara Bar-Serapion, and contemporary Rabbinical sources. One thing to note about those Contemporary sources: The miraculous events the surrounded Jesus were NEVER DENIED OR PROVEN WRONG by those contemporary sources. Instead they were explained away as sorcery. By the way, there is no sperating the 'nice guy'[(who chased money changers out of the temple with a whip twice!), with the miracle working God-man; they are inseperable.
Check out the impressive bibliography of "The Search For The Messiah" by Mark Eastman, M.D. and Chuck Smith
I did cut and paste this to be clear. I am not claiming to be the author, but I read so many that basically repeat the same historical references as to the existence of Jesus, before you even consider the bible, or the millions of followers of his teachings.
You do know that Tacitus never travelled to "Germania", but you regard all of his testimony as absolute fact? Does that mean what he spoke of is inaccurate? No; but it does show that his information is likey from word of mouth, basically second hand sources.