Remember that National Association of Pastoral Musicians’ survey from a while back, asking for the titles of "songs that made a difference" – referring to music used in liturgies? No? Well, they had an online survey to that effect. I don’t see any publication of say, the top 50, which would be interesting, but here’s a sampling of responses that they’ve chosen to publish. It’s alphabetical and selective. So.
Thanks to Todd, a link to the report, which does, indeed, exist.