A chapter break is an important psychological spot in the book, because you, as the writer, don't want the reader to use it as an excuse to put the book down and go do something else. You want them hooked so they just keep reading right through to the next chapter, and then the next, and so on. One advice I heard somewhere was to never end a chapter with someone walking out of a room and closing the door behind them. Apparently this is some sort of mental signal to close a book.
Anyways, for me, chapter endings--I usually try to make them cliffhangers of some sort, either throwing in a piece of unexpected action, dialogue, or a sense that something is going to be revealed or has just been revealed. I guess you could literally string readers along if you wanted by cutting off a sentence midword and picking it up in the next chapter so they have to keep reading to complete the thought..but of course, that might get annoying fast.
I also end chapters on natural breaks like perspective shifts, scene changes, and so on. One other piece of advice I try to follow in this is summed up as "Never take the reader where they expect to go, or show them what they expect to see." Keep them surprised by where the story is going, or what is happening to the characters. If they expect the next chapter to be the hero going to the rescue, pull a switch and perspective shift, perhaps a developing subplot that is going to make the rescue that much harder to pull off (this can be difficult, of course, if you are writing first person stories). Then the reader not only is pulled along by the continuing chaos, but since they already want to know how the rescue gets pulled off (or not, as is often the case) they will continue for at least a few chapters until the story gets back to that thread.
That's my two shiny round metal money units.
www.jrvogt.com