[Swarm Modelling] painting apps

[Scott Christley]

I know this isn't a modeling question but hopefully those of you 
writing papers which include graphics have found a solution.

I'm looking for a basic painting application with tools for drawing 
graph type structures; circles, boxes, curvy lines(bezier curves), 
arcs, arrows, labels, that sort of stuff, but not with freehand which 
will just look sloppy.  The app should also be able to export the 
images into a format that can be processed by LaTex, encapsulated 
postscript (EPS) being optimal.  Lastly, I want it to run on Mac OSX 
but I'm also open to any free software for GNU/Linux.

I know I can probably buy one of those expensive Adobe packages but 
that seems overkill for the type of stuff I want to paint.

Any suggestions?

thanks
Scott