Asymptote is a powerful descriptive vector graphics language for technical drawing, inspired by MetaPost but with an improved C++-like syntax. Asymptote provides for figures the same high-quality typesetting that LaTeX does for scientific text.
9 hours of trying to install it. I've got a Mac OS X 10.6.4 and I'm close to tears. Tried near on 50 times just because of time already committed, and I only wanted to do a picture for a presentation.