If the Bible is fractal or holographic - such that each unit contains the whole - then it should not matter much which part is the focus (so long as the spirit is right).
But my favourite book of the Bible is and I think always has been the Gospel of St John (in the Authorized/ King James Version, of course) - a profoundly un-original preference, and indeed exactly what would be expected for the kind of person I am.
(Behind this would come the first Epistle and the last section of the other book by John: the Revelation or Apocalypse; and the Psalms.)
Why? It is, I think, a matter of connection - these are the parts of the Bible when I most often feel a connection flash across 2000 years; and then the feeling of warmth and yearning slow-burning in the heart.
And this, in turn, seems to be a matter of personal identification with John himself - to me the most love-able of the persons in the Bible; the one I would most wish to have known.