I dunno about 10... I might get there eventually... In the meanwhile, I'd agree with Harold Godwinsson & Wilfred Owen.

Hmmmm... How about Archduke Franz Ferdinand of Austria-Hungary. The agitators who killed him & his wife managed to assasinate the one bloke in the regime who had both the power & interest towards helping them. WWI might have kicked off anyway at some point, but the world would have been a very different place, I think, if FF had lived. Don't know whether it would have been better, just very different...

Oh & on the subject of Jesus, there is a well argued theory ("Jesus the Man", by Barbara Thiering) that says he didn't die of crucifixion, but lived into his 60's.