Michael Heiser has done a respectable job studying this issue in depth and has written several papers which directly speak to this issue.
http://www.michaelsheiser.com/
In one such document he looks at the modern terminology we use to categorize religious belief systems: monotheistic, polytheistic, henotheistic; and concludes that none of them adequately defines the world view of the hebrew people:
http://www.thedivinecouncil.com/MonotheismProblem.pdfThe proposal offered here is that scholars should stop trying to define Israel’s religion with singular, imprecise modern terms and instead stick to describing what Israel believed. “Monotheism” as it is currently understood means that no other gods exist. This term is inadequate for describing Israelite religion, but suggesting it be done away with would no doubt cause considerable consternation among certain parts of the academic community, not to mention the interested laity. “Henotheism” and “monolatry,” while perhaps better, are inadequate because they do not say enough about what the canonical writer believed. Israel was certainly “monolatrous,” but that term comments only on what Israel believed about the proper object of worship, not what it believed about Yahweh’s nature and attributes with respect to the other gods.
