Recently, one of my parishioners gave me a copy of A Commentary on the Psalms by J. M. Neale & R. F. Littledale. He gave it because we are currently studying the Penitential Psalms, and I lamented how the translation of St John Chrysostom's commentary on the Psalms does not contain comments on each of the 7 Psalms.
The Neale set is four volumes and is by no means not a new production. And it's a set I've desired for some time. It's packed with patristic commentaries on each Psalm as well as the liturgical use of the Psalms according to a number of usages (Gregorian, Ambrosian, Byzantine, etc.)
For those who are looking to buy their priest a great gift, or for those who are interested in an excellent resource for the Psalms, I highly recommend this set. It's not cheap, but it's worth every penny. You can purchase your copy here.