They were my constant companions for the last year as we studied the Books of Kings in the Old Testament.
I recommend each of these commentaries for their unique contribution:
Dale Ralph Davis, 1 Kings: The Wisdom and the Folly & 2 Kings: The Power and the Fury.
Dale Davis writes my favorite commentaries for help in preaching Old Testament narrative books. He is an bona fide OT scholar and it shows, but his commentaries are edited versions of his sermons on through these books, so they are pastoral and practical, as well.
Iain W. Provan, 1-2 Kings (NIBC)
Provan is a master of concision and always sees something that the other commentators miss. His book forms the basis for the notes in the ESV Study Bible.
Peter Leithart, 1-2 Kings (Brazos TCOTB)
Leithart is good for opening up maximal possibilities. I don't pick up everything he lays down, but he makes fascinating connections between various themes, words, characters, and other items across the testaments.
Paul R. House, 1-2 Kings (NAC Vol. 8)
If I was only allowed one commentary on 1-2 Kings, I would probably buy this one because House does it all in solid workmanlike prose. He's not as fun to read as Davis, but he really gets the job done. I always checked everything I planned to say on Sundays against the discussion in this book.
August H. Konkel, 1-2 Kings (NIVAC)
I've had Konkel's commentary the longest of the set. I used it to teach the youth boys' class the books of kings a few years ago, and it served me well. As with others in this series, there is a major emphasis in each section on application to life.