A good song is one that can showcase many different techniques. You could go for one that easily proves your technical ability like Eruption, but I suggest one with more structure and layers. I suggest a shorter version of Paradise City: Play the opening arpeggio, play the verse riff (sing a verse or whatever), and play the solo.
If you can do this, not only will they see you as a good technical soloist, but also as a good rhythm guitarist.