LaTeX
As my colleague James Kirby put it "LaTeX is really the only way to fly when it comes to putting papers together, particularly if you're doing semantics, or want to format anything mathematical." I use gwTeX with TeXShop on Tiger (that's Mac OS 10.4).
I only have a few bits of advice to offer linguists using LaTeX.
Opinions on how to solve linguist's typesetting problems. Most of these are my comments on some of the solution suggested at the LaTeX for Linguists page.