I agree with Terra, but sometimes it does keep you going. Say if it's very late, and you've resolved to stop reading at the end of this chapter. Then you see the next chapter title and you have to keep reading. Not every chapter can end with a cliffhanger.
I think it's purely circumstantial. If you're writing a children's or young adult novel then chapter titles might be useful, especially if the chapters are long (15-20 pages each). But writers such as Dean Koontz and Dan Brown, who write many, many short chapters (3-5 pages each, and up to 80-120 chapters per book) don't use chapter titles. To do so is just excessive and pretty annoying to readers. But perhaps naming them yourself for your own records, so it's easier for you to sort through them during the editing process; I can the usefulness in that.
One thing I noticed, is that it seems to be largely the fantasy genre that employs the use of titles.
Unless you feel it adds something very special to your books and/or chapters, there is no need to. However if you like it, you could. There is no one that can tell you what you must or musn't do. This is your book! If it is your style as a writer to name your chapters, you should. I don't think it makes a significant differance for the readers experiance.
where it might make some difference is in submitting the work to agents/publishers, if they see your having done so as amateurish, which would be likely... however, even if that should be, it's the ms they'll be more interested in and if that's well-written, has good market potential, and they're interested in repping/publishing the work, they'll probably just tell you to lose the chapter titles...
One thing I don't like about naming chapters is that after a while it can be difficult to come up with original titles that don't sound cheesy. I don't think titles are always necessary. Chapter titles, in my opinion, work best for fiction pieces and don't always need to be added to nonfiction pieces unless the author wishes to do so. ~Eliza
I'm not sure if this has been brought up yet, but how about titling groups of chapters, rather than individual chapters? One example of this that comes to mind is William Gibson's Neuromancer. It has 20-some chapters but they're divided into three or four (sorry, it's been a while) titled sections. One obvious advantage I can see is that a book with lots of chapters won't require lots of titles, for those who like subtitles.
