Avogadro Software for Windows and Mac [Download]

Avogadro is an advanced molecular editor designed for cross-platform use in computational chemistry, molecular modeling, bioinformatics, materials science and related areas. It offers a flexible rendering framework and a powerful plugin architecture.

Features
International: Translations into Chinese, French, German, Italian, Russian, Spanish and more
Intuitive: Built to work easily for students and advanced researchers both.
Fast: Supports multi-threaded rendering and computation.
Extensible: Plugin architecture for developers, including rendering, interactive tools, commands, and Python scripts
Flexible: Features include Open Babel import of chemical files, multiple computational packages, crystals, biomolecules, etc.

Legal Notice:
I am in compliance with eCrater and an authorized seller of this software under the GNU/GPL license, which allows for reselling.