ComputerGraphicsKit (http://cgkit.sourceforge.net) for creating 3D computer graphics images
pythonCascade is going to be a complete Python wrapper for Open CASCADE, one of the three major modeling kernels available on the market today http://www.pythonizer.org/pythoncascade/pythoncascade.html
MayaVi A library and application for scientific visualization based on VTK.
Charts and plotting:
libploticus (Python wrap for Ploticus) seems not to be mentioned elsewhere
PyX (http://Pyx.SourceForge.net) - Python graphics package generates EPS
See also SciComp plotting