After seeing the $600 price tag for Adobe Illustrator, I am especially interested in learning open source solutions for finishing maps created in a GIS. What open source, or commonly available, software do you use to add the finishing touches (e.g. arrows, textures, colors, graphics, text, etc) to maps created in Arc, QGIS, or your choice of GIS software? Examples welcome.
I use Inkscape: http://inkscape.org/
See this popular thread: What free programs should every GIS user have installed?
From there I would suggest Gimp and Inkscape. Scribus may be interesting too, if you have more complex publishing needs.