I am a extensive LaTeX user. Nowadays, I prefer using org-mode to save some keystroke, but I always compile my org files through LaTeX. This page describes several hack of my own with LateX. Please see also Tools for the specific hacks I did for my teachings.

LaTeX-beamer style for lectures

Here is my own class of additional macros I use over beamer: beamerthemeEmptty3.sty (version of 20101117; please ask an update if/when it gets outdated).

The main point of them (beside of the cosmetics of the result and the cruft of the internals) is that your presentation have a "prof" (teacher) mode and an "eleve" (student) mode. In teacher mode, you have the notes plus the result of the tiny exercices I love to ask during my lectures.

There is also a \trou macro which I use very often during my lectures. Its content is displayed in the beamer version and replaced by an empty box in the handout version. I hope that this way, the students do [come and] listen during my lectures, even if they have an handout.

LaTeX style for exercise sheets

There is many similarities between this style and my beamer style above, but with specificities for exercise sheets. All my sheets can compile in 2 versions: either problem statement or answer sheet. The former is obviously for the student to take the class. The second one is a bit misleading as most of the time, the additional information are not for the student to understand their errors, but more to help the teaching asssistant in the preparation of their intervention.

Nice looking presentations

All my presentations are compiled with LaTeX. I use two main packages for this. The first one is latex-beamer, which you can find on most linux distributions. The second one was developped internally with some friends of mine (Arnaud and Vince). It's called latex-make (earlier named figlatex and latex-utils), and it's part of Debian by now. It makes it easier to compile a document, taking care of compiling all dependencies accordingly.

These days, I use xfig only when in a rush. If I want to get a really nice looking presentation, I go for inkscape, which a neat tool. Getting a result is much faster than with tikz, with which you will lose so much time on the visual appearance of the result that you will forget to generate any result at all.

I also have a little script recompiling the latex and updating pdf viewer for me. Example: tex watch slides.pdf

Advantages of this approach

You build LaTeX documents, not powerpoint cruft. Maths look really better, it's vectorial so the sizes are only the half or even less, and the table of contents are both automatically computed and links to the right slide.
Latex-make can track every dependency of your LaTeX files, and rebuild the parts which needs to be to give you the PS or the PDF you want. It can deal with references and citations of course, but also with multiple bibliographies, indexes, glossaries, ...
You can produce LaTeX files containing figures and which can still be compiled to both PS and PDF: just include your .fig files you generated with Xfig, let the Makefile generate the files to include automatically, and finally, the LaTeX magic from the package does this inclusion for you.
So, you add \includegraphics{myfile.fig} in your document, and it automagically regenerate the pdf version, and include it.
It allows you to build animations with very little effort. Parts to be displayed at the different steps must be placed in different svg depths. Then, you write a little file describing which depth must be displayed at which step. Finally, you append a "subfig=<step number>" to the optional arguments of \includegraphics (\includegraphics[subfig=2]{myfile.fig}, \includegraphics[subfig=2]{myfile.fig}, etc) and the Makefile extract the right depths in new generated .fig files and export them to ps or pdf automatically before inclusion. But that's by far the best solution I've found to make presentation animations.
With beamer, you can build animations which are really hard to build with powerpoint, if not impossible. For example, have some text arriving at one step, and leave not one, but 3 steps afterward.
You cannot build inter-slide animation where graphics arrive in a furry, turning all around the place. But this is just polite for your public, IMHO.

Some examples

The source of the lecture on advanced algorithms in SDR is available, and should be quite up to date with my LaTex presentations know-how. In particular, it's full of Tikz magic...
A scientific presentation on automatic network discovery: the source and the resulting pdf.
An outdated introduction to myself in french using a full load of beamer tricks: the source and the resulting pdf.
An old lecture on recursivity (in french): the source, the handout version and the beamer version.
I have other lectures available, but since I don't want my student to get the teacher version of the handout, I only give them on request. But I happily do so when I'm asked for.