While we're on the subject of Vai's songs, I'd say my favorite tune of his is 'Tender Surrender'. That song has sooo much passion and conviction. You can feel the soul in his notes and the voicing of his solos. That, in my opinion, is the pinnacle of a great guitar-featured song. It's not the craziest alternate picking, sweeping arpeggio, shred-fest, but a tasteful piece with bone-chilling guitar playing and it raises the hairs on my head.