Almost all Japanese emperors for the last 700 years have had names ending in "hito". What is its significance?
Hmm, well from my quick googling, the kanji 仁 from Akihito (明仁) and Hirohito (裕仁) means perfect virtue benevolence charity affection love (http://www.saiga-jp.com/cgi-bin/dic...=仁&g=&e=&s=&rt=0&start=1&sid=1383804641_42356) So maybe it is just popular. These are their given names anyway I believe, and people in Japan call them by other names (http://en.wikipedia.org/wiki/Emperor_of_Japan#Addressing_and_naming).
Japanese first names (the equivalent of a Christian name) usually consists of between 1 to 3 characters. In the case of the current emperor - Aki and Hito. Each character has its own meaning and therefore the combination of two characters creates a deeper meaning. It is highly common, when naming a newly borne child, to take one of the characters from the grandparent of the same sex and infuse it with an entirely fresh character to complete the full name. It is common but not universal. Incidently, no one in Japan calls the emperor Akihito, or the previous one Hirohito. While they are living they are referred to as "Tenno", literally "emperor". Once they have died they take on the name that has been predetermined and that has been used in calendars. So no one says Hirohito, rather they say Showa. The current calendar say it is the 25th year of the Heisei era, that is to say the 25th year since Akihito ascended to the throne. When Akihito dies, he will be known not as Akihito but Heisei.