Back when I worked for Promega Corporation, I created a bunch of molecule renderings for their marketing materials, using Blender and Modo.
Some of my favorites, however, were never used for any campaign. This rendering of the AKT protein, done in Blender, reminds me in style and mood of some of my favorite Escher prints.
Here’s a set of non-photorealistic “sketch” style renders of various molecules and other biological minutia:
Some other miscellaneous molecule renders from that period: