Though many congregations once knew how to sing in parts and read music, the art of congregational singing is being lost as many churches move to "praise bands."
One might notice that churches in films which are portrayed positively, tend to sing hymns in parts. By pointing this out, I mean no judgment upon the vast majority of churches which don't; but simply: good congregational singing is in no sense something which estranges new people or visitors. In fact, I'd think that it generally would be seen as a lovely thing by newcomers - as evidenced by mainstream media's selection of congregational singing for evoking positive images. I believe "praise band" music to be popular largely because small children more easily understand it, its being so similar to the songs they hear on the radio and in shopping malls. Unfortunately, praise band style music in many churches is likely to be experienced as odd by many newcomers, and is experienced by many as an acquired taste (and not always easily acquired).
Congregational singing in parts is, on the other hand, a beautiful demonstration of the harmonious diversity within the body of Christ, with the congregation itself being the main instrument of praise, rather then being like "back up singers" for the band standing in front.
This is a hymn sung by a Mennonite church. Not bad at all for congregational singing. It's part of Youtube user w3tno's collection of videos - mostly of congregational singing. It is a valuable resource if your own congregation is interested in congregational singing - either to inspire them, or for listening to how other congregations have sung these hymns as an aide to learning them.