Most schools have a list of novels approved as "college bound" that meets high standards...any of these will be fine.
Some of the better books out there (classic category) are by Ernest Hemingway...A Farewell to Arms, The Sun Also Rises, etc...
with the recent death of Joseph Salinger there is a lot of interest in The Catcher in the Rye...
I am a big fan of Louis La'more's The Daybreakers...(western category)
In the Science Fiction category...I would recommend Isaac Asimov's I, Robot... and several books by Michael Crichton including State of Fear... also Jules Verne's 20,000 Leagues Under the Sea (that my 8 year old son is currently reading)... and Orson Scott Card's Ender series (begins with Ender's Game...most of my students really enjoy reading this one...)
In Fantasy category...I recommend J.R.R. Tolkein's Lord of the Rings trilogy (Fellowship of the Ring is book 1) or the Robert Jordan's Wheel of Time series (12 books to date) beginning with Eye of the World
If you want to scare yourself silly then read any of the Richard Preston books (Hot Zone and Demon in the Freezer are both non-fiction, while Cobra Event is a fiction story...btw these novels are absolutely graphic in detail...I have had students throw-up after reading parts of these books...)
A recommendation from a teacher...read, read, read...there is nothing better that you can do to improve your knowledge base or education...