I can't really speak to the whole lyrical aspect of things, having been born in 1964 and therefore too young to have really participated in the cultural debates about The Beatles. However, as a young adult folkie, even amongst blue grass crowds, we often got requests for Beatles songs that people weren't even aware WERE Beatles songs such as :

Mother Nature's Son
Dear Prudence
Here There and Everywhere
You Won't see me
Golden slumbers
For No One

In 1990, I cam across a marvelous record by John Arpin, a Ragtime pianist who did totally faithful Ragtime renditions of about 12 Beatle's numbers which sounded almost perfect in that tradition. I don't know if that record is still available, but I have the cd and wouldn't mind swapping mix-tapes if somebody can hook me up with some instrumental Beatles covers of their own.

People have mentioned songs like "Let it Be" and "Imagine" which have entered into the group mind and pop up when people start singing to coslole themselves. I think that is the true test of a song-writer's mettle. I've sung "Imagine" at a huge sit-in in 1986 to protest the firing of an openly Gay Music Professor in Albany NY. We had about 500 people and the TV cameras didn't bother to shoot anything until somebody started strumming the chords to "Imagine" and the entire group began to sing. That was some momnent. "Across the Universe" is another one of those songs that just pops up at the right time too.

Then there are the less serious songs which people just love to sing. Ringo starr's VH1 Storytellers CD is a great example of that. The recording of "Love Me Do" on that record is hands-down fabulous and shows you how even a silly little song can be great fun. There's also a great version of "Don't Pass me By" on that CD .. a song which I've heard a few Jug Bands take up quite nicely.