OK, got the %!*@%! taxes done, so I can get back to y'all's scintillating discussion!
Harryoldham [and others],

Why is a congregation singing hymns necessarily a different beast from folkies singing around a campfire [or a pub table, for that matter]? Group singing has many payoffs quite aside from theology.

Chipper, there's "practicing," and then there's "practicing." The first run-through of a play and dress rehearsal are both "practice."

McGrath, yeah, songs don't have chords per se," but with 3-part harmony, they do. In a jam session, if the pickers are using chord patterns that are compatible with each other's, it sure sounds better than if they aren't. And some chord pattens pretty much preclude some harmonies. [Much to my chagrin, the current Unitarian hymnal has a [piano] arrangement of "Amazing Grace" that makes the exquisitely beautiful high harmony that is often sung with that song sound weird, because the chords don't fit with it.] A melody may not "have" chords, but it does to some extent circumscribe the chords and chord sequences that will "fit" it.

Dave the gnome, re people who "dislike singers using lyric sheets [yet] seem to think it is OK for a poet to use a book," I' m reminded of when I saw Basil Rathbone do dramatic readings when I was in college. Superb entertainment undiminished by his having a book on the lectern.

Carol C., I like your neologism/acronym for that common disroder "CRS." [BTW, have you got the stuff with the codeine in it? It'll suppress your cough, all right, but coherency is sure to be a casualty. Get over that cold now, okay?]

Russ, I think you're getting to the main point about where, when, and why to use books or song sheets.
Personally, though I have a couple thousand songs committed to memory and still find lryics easy to memorize, I still use or advocate lyric sheets when:
• I'm singing in another language, especially one where my pronunciation is far better than my comprehension,
• I want to encourage the whole group to sing with me--because it's a good song for a group to sing--and they don't all know it.
• The combined lyrics and chords are such that, even though I've been doing the song from memory for years, there's a danger of blanking on one or the other in a live performance. [I seldom do a recording session without the words and chords in front of me, precisely because the demand to do it perfectly greatly increases the chances of drawing a blank somewhere in the middle of the song!]
• [Sometimes when] I'm doing in front of a live audience a new song that I've rehearsed many times with no audience--'cause the change in ambient conditions may produce a blank and I'd druther not blank.

And, oh, a lot of big shot performers are using teleprompters or some sort of electronic cue card--just as "prompters" were used in the theater from Shakespeare's time.

In reply to your question, John R.: yup.

Joe_F,
"By [the] time... we had heard the tune so many times ... we knew it." Yeah, but you were--what?--six?

Abuwood,
I agree that the consensus seems to be "learn it if you can, but don't knock those who can't." I'm not sure there's consensus that using a book "like singing hymns in church" is bad if it's an informal song session just for fun.

John G., I once heard a music teacher remark that we never say to a child who walks or talks awkwardly, "You can't walk," or "You can't talk." So why do we say to one who doesn't sing beautifully "You can't sing." I would add that if someone were truly "tone deaf," as many like to say they are, they wouldn't notice if someone else were off key--but they usually do.

Genie