[1]: http://johnmacfarlane.net/pandoc/
While Beamer is fine, you can also generate HTML-based slides with both Org-mode and Pandoc. You can use MathJax for the math. I personally prefer HTML slides, but it really is a matter of preference. (I also find it easier to customize with CSS than LaTeX.) The real beauty is that you can use the same document to generate both, so it's easy to try each option.
More generally, I find using Org-mode or Markdown far easier than any WYSIWYG program. Life is much easier when you separate the content from its presentation.
Type in your equations/math, hit render, drag the PDF (or many other image formats) to your slide.
LaTeXiT gives you the best of both worlds; wonderful rendering of math, with the bonus of using Keynote (which is the best presentation software on any platform in my experience).
FWIW, I started feeling much better about presentations once I convinced myself to view the audience as friends who are trying to help me understand the material I'm presenting, rather than a group that I needed to try to impress.