Janis Joplin, Jimi Hendrix, The Who and many others influenced what became metal. I was listening to them before I was listening to metal. Then when I started listening to metal I went back and listened to bands like Wishbone Ash, King Crimson and others because their music is fantastic and so easily related to the metal I was listening too. I've never confined myself to one form of music and let it get stale or get bored by it. My missus does that, listens to the same albums over and over and over again. The same band could have five albums but they all blend in with each other and become the same after a while.
Apart of anything this forum has shit loads more than just metal, unfortunately (for me) there is a lot of black metal talk which I'm just not into and there is a lot of fighting and dick swinging, even by the female posters, but the variety here is brilliant, so many new bands in so many different genres get talked about.