It may change someday but for the last 2.5 years, this has been Grayson's favorite song his grandfather sings (at least, since he's been old enough to communicate it by pressing "repeat" on the CD player and vigorously shaking his head "NO!" when any other track sneaks in).
Other favorite songs remain:
Long Black Train by Josh Turner Light of a Clear Blue Morning ("The Fast and Slow Song") and Baby, I'm Burning ("The Pistol Song) by Dolly Parton I'm A Believer preferably by The Monkees, but also by Smash Mouth