Sex Lives Of Cannibals - This is a really funny book about a slacker who follows his wife to the South Pacific. Funny as hell but only because he's such a hopeless dope at doing just about anything. It's written like a Mark Twain travelogue with lots of humor and some insightful commentary thrown in.
Boomsday - Written by the guy who wrote "Thank You For Smoking". Another funny novel with a political bend. Which is no surprise considering this is William F. Buckley's son who wrote it. Definitely not what you'd expect.
A Short History Of Nearly Everything - This book looks much more serious than it really is. Bryson describes one guy as "in every picture it looks as if magnets are placed out of the frame and are pulling very strongly on his hair." This one is really funny but ALSO will learn you a few things while you're reading it. He does a great job of making science interesting and funny all at the same time.
Anything by John Scalzi. - This guy has rocked my world in the last two years. I would start with "Old Man's War" assuming they aren't militaried out from a reading stand point. It's a trilogy so in order it is Old Man's War, The Ghost Brigades, and then The Last Colony.
Joe Haldeman is good too. - He writes military sci-fi as well, but different. Joe Haldeman grew up reading Heinlein and his ultra-patriotic, flag waving brand of military sci-fi. Then Joe went to Vietnam. His books are seen as a response to Heinlein. He came back and wrote The Forever War, Forever Peace, and Forever Free. He wrote a lot of other stuff but those are the good ones.
Paolo Bacigalupi is very innovative and not military spec sci-fi at all. - I read two of his books. The Wind-up Girl and Ship Breaker. Good stuff. I liked Ship Breaker the best. Windup Girl could be hard to decipher at times and had too many characters to easily track. If you like complex sci-fi then you'd like Windup Girl better.
I like Apocalypse fiction. Octavia Butler writes some of the best. - This chick is anomaly. She was black and a woman, writing sci-fi. Unheard of so her perspective is completely different than your usual macho white guys. Again, a trilogy so start with Parable Of The Sower. That's the beginning. Think of the U.S. as a third world country. That's the setting. People have made their neighborhoods into fortresses and still aren't safe.
Xceler8x, why do you read such depressing, violent E36 M3? Because I can then read Christopher Moore and laugh my ass off. - Chris Moore is hilarious. Read Lamb first. The story of Christ's lost 33 years. Christ learns Kung Fu. He studies under a Yogi. He learns from his best friend, Biff, what sex is like with Mary Magdalene. He also wrote some vampire books which completely take the pretension out of the genre. The first vampire book is Bite Me: A Love Story. If you have ever read Shakespeare, Fool by Moore is incredible. I neglected my wife on our honeymoon while reading this one. If you call "neglecting" making the waiter bring our drinks to the pool side instead of getting them myself.