if beginner i suggest ac dc (someof them) just to be rockin! Nirvana and metallica i guess....though i m not a big nirvana fan. chords from van morrison, beatles etc. cuz most old stuff is easy

intermediate is gnr absolutly,

advanced is once again gnr, and some old stuff like lynard skynard ...some van halen....it is for your dad you said right? then lynard skynard for sure!