1. "Bleak House", by Charles Dickens. Arguably the greatest work by the greatest English novelist. Genre: mystery
2. "Pride and Prejudice", by Jane Austen. Witty and clever. Not just for girls!
3. "The Count of Monte Cristo", by Alexandre Dumas. A rollicking good adventure story.
4. "King Solomon's Mines", by Sir Henry Rider Haggard. Perhaps the greatest adventure story every written.
5. "She", also by H. Rider Haggard, for the same reason as #4.
All in the public domain and downloadable here.