I'll echo the recommendations for His Dark Materials by Phillip Pullman, and A Confederacy of Dunces by John Kennedy Toole, and the Chuck Palahniuk books (though I found his last one, Haunted, a bit tough going). Palahniuk wrote "Fight Club" upon which the movie of same name was based.
Others I would recommend -
Douglas Coupland (Microserfs and Generation X being the most famous)
Harjuki Murakami ("The Wind Up Bird Chronicles" being the place to start).
James Ellroy (LA Confidential being most famous)
Arthur Nersesian (fantastic american author whom I've never seen in Irish shops, but well worth the effort over amazon).
I also enjoy Richard Russo, Lawerence Block and Walter Mosley. But I would put these in the same "throw away" category as James Patterson, Dan Brown, James Herbert et al.