I like 'normal' metal and hard rock. Mostly 1970s and '80s but there are some new bands I like; such as Alestorm, Bullet, and GaMetal. GaMetal technically isn't a band, they make metal covers of video game music.
For actual classic metal bands, I like the obvious stuff; Ozzy Osbourne, Black Sabbath, Dio, etc, but there's also some really obscure great metal bands, like Metal Church, Jack Starr's Burning Starr, Alcatrazz, W.A.S.P, Dokken, Sabaton (Not very obscure, but Joe Schmoe up the street probably doesn't know them), Yngwie Malmsteem (Technically not a band), Caesar's Palace, Manowar, Running Wild, etc. Also, Black Flag is an obscure punk rock band from the late '70s and early '80s.