True, a good hook is very important. A lot of people, when they're ambivalent about whether or not to read a story, will open the file and scan the first screen or two... and if their attention is not caught, they'll close the file again.
Also, I've got a book on writing* that says *every* scene ought to end on a disaster -- some dramatic set-back or twist, that will keep the reader intrigued rather than giving him/her a good stopping point. That's not as big as a full-fledged cliffhanger, but it's the same idea. Always leave them wanting more.
PJ
*the book is called "The 38 most common fiction writing mistakes -- and how to avoid them" by Jack Bickham. It's a fun read
