Saw this today on Grognardia: GROGNARDIA: A Common Culture
Where I grew up Metal and D&D were hand in hand. My first DM was a fan of Iron Maiden and other NWOBHM bands like no other I have since and my next, more regular DM was a fan of all sorts of metal, but also Rush. The covers looked like D&D books, complete with swords, magical looking figures and monsters. It was hard to tell where one had influenced the other.
A quick look at some of the titles of game adventures I have written over the years also shows how deeply I felt this connection: "Veteran of the Psychic Wars", "All Along the Watchtower", "Rainbow in the Dark", I even built an entire series based on the premise that music and RPGs are a natural fit, "The Hex Girls".
I guess though it has a lot to do with where you grew up and when.