DH Lawrence
Arthur C Clarke
Christopher Koch
Margaret Atwood
Barbara Kingsolver
John Wyndham
Kazuo Ishiguro
J Auel
JM Coetzee

Suse i am also impressed by Eco, never managed to get far into any of his.
Catrionlee, definitely a few for the mind there! Agree, Sagan is intense, but I loved Contact.

For any book lover I just read "The Uncommon Reader" a novella by Alan Bennett. Only takes a couple of hours and it is delightful. In short the Queen becomes obsessed with books after a chance encounter with a mobile library in Buckingham palace.