Black Sabbath, Led Zeppelin and Judas Priest
The Who is what decided this for me. Though I like quite a few Who songs, that is as far as I go with them. In my 35 years of listening to rock, I finally bought my first Who album just last week. (Who's next, on vinyl.)
I love everything about Sabbath, Zeppelin, & Priest, and can listen to most of their albums from beginning to end.