[Edited by mkeywood, 7/5/2010 7:10:40 AM]
Chuck Palahniuk, Brett Easton Ellis. They write transgressive fiction; quirky, violent, sexual, often grotesque, usually funny.
William Gibson, Bruce Sterling. They write cyberpunk, a scifi genre, that I find appeals to the younger generations who have grown up with modern technology.
Robert Heinlein, Philip K ****. They also wrote scifi, but with philosophical points of view. Despite being scifi and often having silly plots, they're serious writers. More serious in meaning than any number of more highly respected authors.
James Ellroy, Dashiell Hammett. Hard boiled, film noir style, detective stories. Not like classic mystery stories with the doddering old lady who solves obvious crimes of the upper classes. They're dark, pessimistic, nihilistic, brutal and violent--which agrees with the younger generations.
Dragonflight by Anne McCaffrey is a good choice for Fantasy novels, and an excellent start to an excellent series.
Dragons of Autumn Twilight is also a great book and a great start to another great series. It has the classic Fantasy setting you'd find in a lot of old (and some modern) RPG's.
If you like the Warhammer 40k Universe (or even if you don't) then the Gaunt's Ghosts series by Dan Abnett is awesome; really gritty and a bucketload of characters you come to feel like you know as real people, especially when anything particularly bad happens to them (and of course it does ;D).
War of the Flowers is also a good Sci-Fi/Fantasy novel with some good WTF moments and well placed humour. Actually, anything by Tad Williams is awesome (I have yet to read Shadowmarch though).
Just thought I'd throw my two-pennies in and give a shout out to some of my favourites. ^_^
To Kill a Mockingbird
The Hitchhiker's Guide to the Galaxy
The Story of Edgar Sawtelle
Those are my favorite ones so far. Just finished reading Montana 1948 and To Kill a Mockingbird for like the 50 billionth time