I found this prayer in the church of St Bartholmew, Trunch, and its words resonated with my own feeling about why these buildings still matter. Apparently it originates in St David's, and appears in Roy Simpson's Celtic Daily Light
O God, although you do not live in manmade temples
You choose to work through them.
Pour down your blessing on this place and upon all who minister here,
That it may be a strength to all who have oversight,
A joy and an inspiration to all faithful Christians,
A home of prayer and devotion
Setting forth to the world a pattern of true holiness and worship.