I've just read through the thread.
[not in any particular order / classification]
Complete set of Awdrey {certainly father & probably son as well}
Ransome, JKRowling, WEJohns [almost a full set in storage, about 20 on the shelf]
Had a complete set of Clive Cussler, but that got culled two years ago [donated to a charity shop].
Tolkien, M Moorcock, plenty of Asimov, Banks, Baxter etc - but most of those went about a decade ago.
Bernard Cornwell, Patrick O'Brian, Alexander Kent
LJRoss [as they're based around here]
[I've also got a lot of Star Trek books, but that is made up from many different authors !]
[also, huge number of railway / engineering books]
I've returned many, many titles to charity shops after a couple of reads ...