CrystalClear Interface 2.1.3 - Customize certain aspects of the Mac OS X Aqua interface. (Free)

CrystalClear Interface (CCI) is a powerful system add-on that lets you customize certain aspects of the Mac OS X "Aqua" interface. Version 2.x adds significantly to the CCI feature set, and is also designed to be easier to control and configure.

The 5 basic sets of interface components that you can customize through CCI are:

1. Window transparency
2. The color of windows and some text fields
3. The "frame" of various window types
4. Miscellaneous items such as scrollbars and the system menubar
5. Buttons, tabs, and other interface widgets

In addition, CCI 2.0 adds several other interface enhancements that you can use if desired:

1. Animating the opening and closing of windows
2. Using "Single Application Mode" (SAM), which reduces window clutter by keeping only one application active at a time. Use the built-in application switcher (command-Tab) to switch applications.
3. For the active application, replacing its name in the system menubar with its icon.
4. Turning off shadows for inactive windows.
5. Using recessed-style popup buttons.