"God Only Knows", Brian Wilson's masterpiece of writing originally sung by Carl Wilson and the Beach Boys, is just that type of song. From the great Pet Sounds album, the original was a thing of beauty and a piece of art.
Take this version, re-imagined for strings by The Brodsky Quartet and belted out by Elvis Costello. The aching in this song is made so much stronger by the arrangement.
Another way to do it is the way Petra Haden did it. Known for her a capella work, she needed her group The Sellouts to pull this song off live, but it remains one of my favorite versions of the song by anyone, including the original. So purely beautiful this version is, and so stripped down.
The Flaming Lips went a slightly different route. They fuzzed up and noised up the original arrangement, but more importantly, they slowed it down. No video for this one, but enjoy the organ part of this song anyway.
For my daughters, here is Taylor Swift. It isn't badly done.
Glen Campbell was part of the touring group of The Beach Boys when Brian Wilson could not anymore. In essence, he partially replaced Brian Wilson on tour. So, to close this post, let me show you his cover of this song, which he did record for one of his own albums (Southern Nights). It's very 70's-country, but still so full of emotion, which Campbell is really good at adding to other people's songs, including my favorite of all time.