Three recent books offer interesting insights into the way ancient Jews and Christians conceptualized the son of God as king, priest, mediator, etc. They also examine sacrifice and ascent. Idel's book looks at medieval Jewish mystical conceptualizations of the "Son." These works provide a number of fascinating insights.
A. Collins and J. Collins, King and Messiah as Son of God: Divine, Human, and Angelic Messianic Figures in Biblical and Related Literature, (Eerdmans, 2008), ISBN 0802807720
Levenson, Jon, The Death and Resurrection of the Beloved Son: The Transformation of Child Sacrifice in Judaism and Christianity, (Yale, 1993) ISBN 0300065116
Idel, Moshe, Ben: Sonship and Jewish Mysticism, (Continuum, 2007), ISBN 0826496660