One old song that I think sounds great on a 12 string is "Walk Right In" which was a hit for the
Rooftop Singers back in the 60's. You really have to dig with your pick to get the sound they had
on that. Another good twelve string song is "Louise", Leo Kottke recorded a version back on on early
album he did. It's a sad song, but a good one. I agree with Ian that "Mr Tambourine Man" makes a good
twelve string song. Or "By the Rivers of Babylon" for a reggae sound.