Fingerstyle-guitarists impress me: They are like one-man-orchestras. It is hard to imagine what kind of physical strain this kind of playing excerts on the body. But naturally that is beside the point: This is music, not sports. I find this crossover of melody and percussion musically impressive in its own right.
One of the youngest rising stars on the scene is Marcin Patrzałek from Poland. He is 18 meanwhile and at the moment making his rounds on Facebook, in a video with a one-man-performance of Beethovens 5th symphony. I find this video here even better: it was made when he was 16 years young and making his break-through.