One can use Beamer to make high quality presentations using Latex code. To know more about beamer and its capabilities visit here and here.

Beamer comes with a set of default templates. However,it has capability to design new themes.

Here, I will maintain a list of beamer themes shared by beamer users. If you know any that are not listed below, please let me know and I can add here for the greater good.

http://recherche.noiraudes.net/fr/LaTeX.php
http://blog.barisione.org/2007-09/torino-a-pretty-theme-for-latex-beamer/
http://www.win.tue.nl/latex/documentation/tuebeamer/tueslides.pdf
http://www.shawnlankton.com/2008/02/beamer-and-latex-with-keynote-theme/
http://www.ist.tugraz.at/staff/weiglhofer/misc/tugbeamer/
http://www.guidodiepen.nl/2009/04/latex-beamer-diepen-style/
http://matdat.life.ku.dk/LaTeX/Frederiksberg/examples.html
http://win.ua.ac.be/~nschloe/content/ua-beamer-theme
http://www.kde.org/kdeslides/
http://latex-my.blogspot.com/2009/10/kde-beamer-themes.html
http://www.cert.fr/dcsd/PUBLIS/THESES/sbouveret/francais/LaTeX.html
http://win.ua.ac.be/~nschloe/content/ua-beamer-theme
http://cameron.bracken.bz/beamer-template
https://bitbucket.org/marczellm/beamerports
http://latex.simon04.net/