1) An amazing site, with hundreds of ebooks divided into Fiction/Non Fiction all on one page. I've been using it for past 5 years now, you can even go on their forum and request new titles which they'll try to upload for you. They do have a download limit of 5 downloads in 2 weeks (to avoid overloading their servers maybe), but that's not really an issue. Here's the link:
http://www.truly-free.org/
2) Welcome to BookYards.com! Our goal is to be "The Library To The World", a web portal in which books, education materials, information, and content will be freely to anyone who has an internet connection. Bookyards has a total of 17,010 books, 41,784 external web links, 4,197 news & blogs links, 384 videos, 32,963 Ebook links and access to hundreds of online libraries (800,000 Ebooks) for your reading pleasure.
http://www.bookyards.com/
3) For Classic Literature (over 10,000 PDFs): In our collection you will find many of the classic works by the greatest authors of history, from the early Greek philosophers and story tellers, such as Plato, Aristotle, and Homer to the great playwrights, such as Christopher Marlowe and William Shakespeare, as well as British romantic poets, like William Wordsworth, John Keats, Lord Byron, and Percy Shelley, plus American writers up to 1923, such as Nathaniel Hawthorn, Herman Melville, Edgar Allen Poe, Jack London. The World Public Library’s Classic Literature Collection is for users of all ages, classic adventure/ghost stories such as Mary Wollstonecraft Shelley’s Frankenstein, Henry James’ Turn of the Screw, Washington Irving’s The Legend of Sleepy Hollow, Louis Stevenson’s Treasure Island, Dr. Jekyll and Mr. Hyde, Frank Baum’s The Wonderful Wizard of Oz and The Magic of Oz.
http://worldebookfair.org
4)
http://www.fullbooks.com/