What are your "must-own" biblical and theological studies reference works?

It just happened again. I had to consult “BDAG,” A Greek–English Lexicon of the New Testament and Other Early Christian Literature (3rd ed.).

I don’t own a copy, so every time I have to consult BDAG I think “I really should buy this.” But for the past decade or so, primarily because of BDAG’s cost ($150 on Logos, $130 used on Amazon, $165 new on Amazon) I’ve held off.

Nevertheless, I’m seeking to build my “must-have” personal reference library to sustain a ministry as a pastor theologian. So, I think I need to buy BDAG sometime soon. While I’m at it, I might as well get HALOT, the Hebrew and Aramaic Lexicon of the Old Testament… Logos sells them as a bundle.

Might as well get the IVP Bible Dictionaries, too. I own hard copies of Prophets and Jesus and the Gospels, but I could use NT Background, Paul and His Letters, Historical Books, Pentateuch, and Wisdom, Poetry and Writings…

How far does the list of “must-have” reference works go?

I’m currently a Ph.D. student in theology, but my project is integrative across the biblical-theological studies divide (Barth, Bonhoeffer, and the Bible). So, I need to have both my Bible and my theology bases covered, both now as a Ph.D. student and in the future as a “pastor theologian.”

What reference works in biblical and theological studies are your “must-owns”?