Publicon

Wolfram Research, developers of the super-sweet program Mathematica, introduced a new program for technical publishing today called Publicon.

It's tough to compete with LaTeX, as LaTeX is 1) free and 2) fucking awesome. On the other hand, Publicon costs money, but it has a graphical user interface. Perhaps Publicon will be popular among those who don't want to spend a lot of time learning LaTeX syntax, but want high-quality output. (And Publicon has a LaTeX output feature, so you can slowly learn how it works.)

As for me, I'll stick with TeXShop. But Publicon is lookin' good so far!