LaTeX is not obsolete at all: in fact it is the standard for writing Mathematics and Physics, but of course it's a great tool for write any type of structured document. Unfortunately it's not very well known outside the mathematical and physical community because of a (supposed) difficulty of use and also because the everage person doesn't need all its power. To have a working LaTeX in your system you should install tetex-extra, tetex-base, and tetex-doc. I sugest also prosper or latex-beamer for
powerpoint-like presentations using LaTeX.