Zsh

The Z shell (zsh) is a Unix shell that can be used as an interactive login shell and as a powerful command interpreter for shell scripting. Zsh can be thought of as an extended Bourne shell with a large number of improvements, including some features of bash, ksh, and tcsh.

After nearly 14 years of using the Bash shell, I have switched to using zsh as my primary shell. It is awesome!