I’m a great fan of Knuth’s TeX system. I use it for papers, markup on literate programs, and slides for talks. I even use it for letters and address labels. For several years now I’ve had a split setup: my Macs use teTeX from MacPorts while my Debian GNU/Linux machines use TeXLive. TeXLive is a much nicer system—it has dozens of packages that Thomas "te" Esser never could ship with teTeX. But the convenience of using MacPorts kept me with its teTeX package.

I’m now delighted to have discovered MacTeX. It’s a Mac-friendly TeXLive package, including DVI previewers, TeX-aware spelling checkers, and everything you’d ordinarily find in a TeX system. It even includes a working XeTeX. XeTeX is a recent innovation to support Unicode and fancy TrueType fonts in TeX. You can just write

\usepackage{fontspec}
\setmainfont{Times New Roman:LetterCase=SmallCaps}

and away you go. It makes it easy to use system fonts in TeX. Now documents produced in ordinary applications (e.g., OmniGraffle) can mesh easily with TeX documents.