I believe in Christianity now because I believe in God and Jesus, but there is another argument in favour of religion comes from sociology, the idea of Emile, Durkheim's idea societal glue.
Durkheim said that religion tended to bond people together to help each other in difficult times to make people bond together like glue.
I think CHristianity provides the best "brand" of glue but I think there is an extent the idea applies to other religion's as well.