The Electric VLSI Design System is a complete Integrated-Circuit design package that handles schematics, IC layout, and even textual hardware-description languages.
A built-in set of analysis and synthesis tools allows Design-Rule checking, Simulation, Routing, and much more. A set of technology files (and a built-in technology editor) let you create any design environment. The system's layout constraint system helps keep circuitry connected, even between different levels of hierarchy. Many different file readers and writers allow the system to interface to the external EDA world. Written in Java, it can run on any platform.
Best of all, the system is open-source and therefore free to all users.