One thing I think I do well as a writer is "hook" the reader in the first paragraph. I was thinking about this today, and I believe I learned my technique by reading Robert A. Heinlein. Heinlein's later plots tended to spin in aimless circles, his characterization was lacking, and his interesting ideas were often buried under a landslide of too much philosophy-- but the man could hook a reader. Some terrific examples of Heinlein's openings:
"Once upon a time there was a Martian named Valentine Michael Smith" - Stranger in a Strange Land (first published version)
"All my life I've wanted to go to Earth. Not to live, of course-- just to see it. As everybody knows, Terra is a wonderful place to visit but not to live. Not truly suited to human habitation." - Podkayne of Mars
"'We need you to kill a man.'" - The Cat Who Walks Through Walls
"I woke up in bed with a man and a cat. The man was a stranger; the cat was not." - To Sail Beyond the Sunset
"As I left the Kenya Beanstalk capsule he was right on my heels. He followed me through the door leading to Customs, Health, and Immigration. As the door contracted behind him I killed him." - Friday
I love writing hooks, but some people prefer books that don't zoom off the starting line quite so fast. As a reader, which do you prefer? And if you're a writer, do your books tend to have a strong opening hook, or do you start a little more slowly?