Was never a big Zep fan back in the day but got to like them as i got older.
There are some bands i didn't buy specific albums but went for their greatest hits the Stones being a prime example.
Have most of what i regard as classic albums or at least something from a classic band.
Zep, Deep Purple, Rainbow, Rush, Sabbath, Dio, Maiden, Genesis, Floyd, Simon & Garfunkel, Allman Bros, Doobies, the list goes on and on but the topic is a bit subjective with regards what you believe is a classic band or album.
Dave