Buy to place on your shelf because everyone has it but you will never read it...
Knowing God - J.L. Packer
Anything written by R.C. Sproul
Institutes of the Christian Religion - John Calvin
Systematic Theology - Louis Berkhof
I have read Packer's book several times over --especially the revised edition.
I read at least a half dozen RCS books in the early to mid 1980s. I haven't read them since then, tough I do have them on my shelves.
With regard to
Calvin's Institutes ,I have read the abridgement, as I mentioned in my first post of this thread.
The two major works of Systematic Theology that I value highly are :
A New Systematic Theology Of The New Testament by Robert L. Reymond, and
Systematic Theology : Biblical and Historical by Robert Duncan Culver. The text of the latter is 1156 pages (plus100 pages of bibliography, index etc.) and I have read every single one assiduously. I have re-read many of his pages to my immense comfort and edification. I bought that one in 2007. I don't know the year I bought Reymond's, probably around 2000. I have read it all and refer to it often, with a lot underlined.