When I first started listening to rock, I liked them & bought a bunch of their cassettes.  When I first stared playing guitar, I listened to them a lot, since their songs are relatively easy to copy.  So, I guess AC/DC is a good "Intro to Metal" band!
I hardly ever listen to them anymore... but H2H, BIB, and LTBR are still great albums.  The rest of their catalog is solid too, of course.