The first song I ever arranged for solo guitar, when I was seventeen years old, was Here Comes The Sun, written by George Harrison, from the Beatles final album, Abbey Road.
If I was ever stranded on a desert island and could have the sheet music for only one tune it would be of this great Fugue by J.S. Bach.
Estrellita by Manuel Ponce was immediately a worldwide hit when it was first sung in the early 1900s and makes a great guitar solo.
Sunflower Slow Drag by Scott Joplin is one of my favorite ragtime pieces to play on the guitar.
Originally written for the piano, the Girl with The Flaxen Hair by Claude Debussy perfectly fits the impressionistic sound of the guitar.
Venezuelan guitarist/composer Antonio Lauro wrote perfect gems for the guitar as heard here in his Venezuelan Waltz #3.