Code::Blocks

The Open Oource, Cross Platform, Free C/C++ and Fortran IDE

Screenshots

Hunter's comment

Code::Blocks can only support multiple languages but this IDE is the best in its type. This is a customizable and flexible IDE for C/C++ developers. The best thing about Code::Blocks is the availability of various plugins. You can expand features in almost every way that might use a special plugin.

Code::Blocks is available on all platforms including Windows, Linux, and Mac.

Intelligent syntax highlighting, automatic code completion and a full-featured debugger will make development very fast.

Link

http://www.codeblocks.org/