I find the look of equations using Microsoft Equation Editor to be truly hideous. Of course you can buy MathType, but why? The native equation editor in OpenOffice is efficient to use, but I still don't like how they look in the document. Despite its age, LaTeX typesets equations beautifully - and there is no reason to discard something good, just because it is old.
Previously, I wrote about how I currently use a plugin called OOOLaTeX, which lets me combine the beauty of LaTeX with the unbeatable price and portability of OpenOffice.
Back to the topic of the post.
It really is easy to use. Just go to Insert->Equation and you can enter LaTeX code directly, or choose symbols from the dialog boxes above.
Here are a couple of screenshots:
I can easily visualize myself using this for presentations.