Old deceased authors from when I was a kid:
Edgar Rice Burroughs: Tarzan, John Carter, Pellucidar, the Venus stories.
Walter B. Gibson: The Shadow, loved them as a kid.
Mark Twain
Shakespeare, I used to go to the library and listen to the records while following along the scripts. I think I was around 9 or 10 at the time. I loved the comedies, hey I'm a guy.
Jules Verne and H.G. Wells
In my teens, all of the big sci-fi writers:
Heinlein, Asimov, Bradbury, E.E."Doc" Smith, A.E.VanVogt although I never have figured out how to pronounce his name, and many others whose names have escaped me after all these years.
Older 'til now:
Stephen King, except when he get unendurably verbose, which unfortunately happens all too often.
Jack McDevitt, a worthy successor to Asimov, IMO of course.
Donald Westlake, the man can flat turn a phrase. His Dortmunder books are a gift to us all.
Robert B. Parker, I've read most of them many times strictly for the repartee of Parker with his friends...and enemies too.
Douglas Adams, his prose floats "in much the same way bricks don't." Wonderful.
H.P. Lovecraft and Robert Howard, everyone has to have a guilty pleasure.
Koontz until he just weirded out and got too religious. Loved "Lightning". Quit reading him about 15 years ago.
Lee Childs, although his first ones were great, the middle ones wordy, and his last couple back to close to great.
Neal Stephenson, way cool although his last one, "Reamde", was not up to his usual standards.
Walter Mosely, gotta love Easy Rawlins.
James Lee Burke, Dave Robicheaux even if he is such a head case.
John Sandford.
P.G. Wodehouse, can't forget Bertie and Jeeves, but I don't like his other books as well.
Stephen Hunter.
Bill Bryson
Louis L'Amour, another guilty pleasure. Bubble gum for the mind.
John Steinbeck.
Larry Niven.
And many more that were already mentioned many times, although there are lots of authors mentioned I've not heard of.
PS I almost forgot Christopher Moore. Great stuff, I mean who knew Jesus had a childhood buddy named Biff.