I devour everything Stephen King and Dean Koontz write, so I guess they'd be my favorites. J.K.Rowling would be on that list, too.
My favorite books are To Kill a Mockingbird (I've read that at least 10 times) and The Mists of Avalon.
Nora Roberts I don't have a specific favorite book but the Bride Quartet is my favorite series. There are 3 of her books that are tied right up there with that series, Midnight Bayou, The Search and Black Hills.
I have MANY favorite authors and books! Just a few are Jodi Picoult, Alice Hoffman, Wally Lamb, Philippa Gregory... Favorite books, I could literally go on and on.
My favorite author is James Patterson and so many of his books were fantastic that I can't just pick one. Right now I have read 46 of his books and enjoyed all but a very few.
I like John Grisham, all of his books are great. I enjoy some of Michael Crichton's books (Jurassic Park and Congo are excellent, Rising Sun. . .not so much). I also like old kid's books, Kate Seredy is my favorite in that genre.
My favorite author is probably still Dr. Seuss, though I haven't read any of those books for... I have no idea how many years (don't have kids to read them to!).
I also LOVE Lewis Carrolll (Alice in Wonderland et al) and Frank Baum (the Wizard of Oz series).
As to contemporary authors, I probably enjoy Robert Tanenbaum and Jeffrey Deaver, though I enjoy reading books by all the authors listed.
The best book I've read recently, however, was Paths of Glory by Jeffrey Archer, a book about George Mallory's life (much debated as to whether he was the first to summit Everest or not - 1924. ...debated because he didn't make it back alive, but they did find his body in 1999, and his wallet was missing the picture of his wife, which he'd planned on leaving on the summit).