Chapter ending symbols was very common in older literature. In the 16th century they could be incredible works of art; however today this practice seems to be almost absent in printing. I have seen graphic designers who recommend its use, because it makes the ending of chapters more graphically pleasing, as you point out.
I am not aware of any predefined ways to do this, but it is not hard to make your own definition of a chapter-end symbol. You could simply define a command that inserts a graphic (remember to add \usepackage{graphicx} in preamble), and then use this command at the end off a chapter. I made myself a nice caffeine eps-file to test this:
\newcommand{\chapterendsymbol}{
\par
\vspace{\stretch{1}}
\begin{center}
\includegraphics[width=125pt]{caffeine.eps}
\end{center}
\vspace{\stretch{2}}
}
Typing \chapterendsymbol will now place my caffeine molecule one third of the way down on the remaining space. This is all well and good, you may have noticed, if there is enough vertical space to fit the graphic in there. To amend this I created a new command, \chapterend, that uses the \chapterendsymbol if there is enough space for it.
I know that my graphic is just over 120pt high, so I figure there should be at least 150pt available vertical space before I use the chapter-end symbol. This can be checked by using the xifthen package. Here is a MWE of how I did this:
\documentclass{book}
\usepackage{graphicx}
\usepackage{lipsum}
\usepackage{xifthen}
\newcommand{\chapterendsymbol}{
\par
\vspace{\stretch{1}}
\begin{center}
\includegraphics[width=125pt]{caffeine.eps}
\end{center}
\vspace{\stretch{2}}
}
\newcommand\measurepage{\dimexpr\pagegoal-\pagetotal-\baselineskip\relax}
\newcommand{\chapterend}{
\ifthenelse{\lengthtest{\measurepage>150pt}}{\chapterendsymbol}{}}
\begin{document}
\chapter{First chapter}
\lipsum[1-5]
\chapterend
\chapter{Next chapter}
\lipsum[1-2]
\chapterend
\end{document}
You could of course use whatever image you like, as long as you make sure you have a sensible value in the \lengthtest{\measurepage>[height]pt}. Better yet, use one of the pages recommended by Count Zero above to create a nice vector image!
This is how my MWE looks. Notice how the first chapter has a chapterendsymbol, but the second doesn't, even though the \chapterend command is used at the end of both chapters. This is because there isn't enough space at the end of that page. (Sorry for the poor picture quality!)

amsthmlets you create your own theorem-like environments. – vonbrand Feb 7 at 3:53TeXbookchapters withraggedleftquotations at the bottom of the last page in a different font. – cmhughes Feb 7 at 4:08