these are not new authors by any means but they are great writers.
Richard Adams, for books like Watership Down and Shardik
Douglas Adams for his dirk gently and hitchhiker's guide to the galaxy books. you will be laughing out loud til it hurts.
Anne Rice for her Vampire Chronicles, i mentioned this already in the movie remake thread and i think she needs a mention here. her non vampire books are alright, but the vampire stuff is easily her best. she is probably the greatest writer on vampires.
Pearl S Buck for her Good Earth Series of books, i started these in the 80s because i had seen the film and figured i would give the book a try, i was immediately hooked and then i moved onto the other installments. its about revolution and the rise and fall of power in china.
John Steinbeck for grapes of wrath, of mice and men, tobacco road, tortilla flat and a bunch of famous others though i have not read them.
Arthur Conan Doyle. there is Sherlock Holmes series of books which made him famous, though he has made some very good fantasy novels like The Lost World.
Laura Ingalls Wilder, for her Little House series of books. yeah they made that shit into a cheesy tv show in the 70s, but that show was maybe ten percent of what actually happened in the books. the hardships she and her family faced while homesteading and trekking across the country (she was only in walnut grove for a few years before she moved further west) will make anyone cherish what they have.
oh and of course Charles Dickens is required reading for everyone and shame on you if you have not read at least 2 or 3 of his books.