Haven't listened to this all the way through, but I've heard the Clare College Choir before and can safely predict it will be musically gorgeous. Best of all: it's a full hour, and you don't have to click from vid to vid to get the whole thing.
I'll come back with some info on composers, etc., if I can. From the YouTube page:
The Anglican Episcopal House of Studies at Duke Divinity School with the Choir of Clare College, Cambridge present Choral Evensong, September 13, 2010, at Duke University Chapel. Choir under the direction of Timothy Brown, Director of Music, Clare College.