These kinda questions are hard because it’s so subjective-- what is ‘best’? Most influential? Most technically challenging? Most recognizable (ie timeless?)
I’d say something that is almost immediately recognizable across all genres that invokes the primal urge to play air guitar.
Certainly Money for Nothing fits that- great choice.
Some contenders (IMO):
Black Dog or Whole Lotta Love - Jimmy Page
Mississippi Queen - Leslie West (Mountain)
Purple Haze - Hendrix
Rock You Like a Hurricane - Scorpions
Back in Black - AC/DC
Unchained - Van Halen
Bad to the Bone - George Thorogood
Smoke on the Water - Deep Purple (I mean, even people who don’t play guitar can play that one)…