Readers working on the "award winner" quest can find lists here. If the entry says "ALA" the American Library Association chooses the winner through a committee of librarians, booksellers and people who teach children's literature classes.
(In a real hurry to grab a book to finish your quest ? Just pick up anything by any of these children's authors who have won prize after prize or by these adult fiction award winners.)
Books for Children
Newbery Award First children's book award in the world (1922), ALA
Caldecott Medal Picture books. ALA
Coretta Scott King Award African-American culture, ALA
Robert Sibert Informational Book Medal Non-fiction books. ALA
Theodor Seuss Geisel Award Beginning readers, ALA
The Pura Belpre Award Latino culture, ALA
The Laura Ingalls Wilder Award Awarded to an author or illustrator, not a specific book. ALA
Carnegie Medal in Literature For books published in the UK, the winning book is chosen by school librarians.
Best Books For Babies Beginning With Books, a Pittsburgh literacy organization, selects a committee to choose winners.
Boston Globe - Hornbook Awards Unlike the ALA competitions, these awards are open to authors and illustrators who are not US citizens. A small panel of judges is appointed by the editor of Hornbook.
Black-eyed Susan Separate awards for children's and young adult books. School librarians and others nominate books, Maryland students vote for the winners.
Nutmeg Children's Book Award Children in Connecticut vote for the books.
Blue Hen Book Awards Nominations made by librarians, winners chosen by the children of Delaware.
Note: some awards, such as the Edgar and the Agatha (see below), also have children't book categories.
Young Adult Books
Margaret A. Edwards Award Awarded to an author, not a specific book. ALA
Michael L. Printz Award "Literary excellence in young adult literature", ALA
Teens Top Ten ALA but ... young adults vote online.
Rosie The Eliot Rosewater award. Librarians nominate, thousands of Indiana highschool students vote.
Adults
National Book Awards The National Book Foundation gives several prizes including one for a young adult book. Nominations come from publishers, and a panel of judges, in part nominated by past winners, chooses the finalists.
Pulitzer Prizes - separate categories for fiction (previously novel), poetry, drama, etc. American authors, American themes. Administered by a board under the aegis of Columbia University.
Nobel Prize for Literature Awarded to an author, not a specific book. The winner is selected by the 18 members of the Swedish Academy for the Nobel Prize in Literature, nominations come from previous winners and academics.
Man Booker Prize for Fiction For Commonwealth and Irish authors, selected by a committee of judges.
Whitbread, now Costa, Book Awards. UK awards in several categories, and for each a small committee of three judges, including authors, chooses the winner in each catagory.
An overall winner is selected by a combination of authors and avid readers.
The many genre-specific awards include the Hugo, Edgar, Ellis Peters Historical Dagger, Agatha, Bancroft ...And many more. Take a look at the Annual Awards wiki.
Edited 10/10/07 to change NBA link from the 2006 to the 2007 list