There's a couple I would go with right off the top;

Definately agree with the Steve Earle suggestions above, but I'd add "Ellis Unit 1" or several of his other story songs. Simplicity of melody and lyrics, and yet pack so much emotion and story in there.

Townes Van Zandt's "Poncho and Lefty". Story with ambiguity. Just captures the complexities of life, loyalty, and with an unbelievably beautiful melody...

Often I include Hank Williams, "Oh Lonesome Me", but heavily borrowing from the Neil Young version. Both ridiculously prolific writers.

I think for all of em it's the simplicity I enjoy. Rich imagery, yet not wordy or over long. Great choruses. sb