I can guarantee you that the best song ever will change based on who you ask. Some might say a Beatles song, while other may mention Michael Jackson, John Lennon, or other legendary artists. Sometimes a person's favorite song changes depending on their current mood. Plus, there are always new songs coming out, so where one might have a favorite song at one moment, the next day it could change. I'd say the best song ever is whatever song is the best to you individually.