ITerm2

iTerm2 is a terminal emulator for OS X on Apple Macintosh computers. It was derived from and has mostly supplanted the earlier iTerm terminal emulator application.

Being optimized for OS X, iTerm2 supports User Interface conveniences such as window transparency, full-screen mode, Exposé Tabs, and Growl notifications. It also uses the OS X standard key-presses (for system clipboard operations, font size increase/decrease, etc.) helping to make it user-friendly for experienced Apple Macintosh users.

References

(1) http://iterm2.com/index.html
(2) http://www.maclife.com/tags/iterm2
(3) http://www.techrepublic.com/blog/apple-in-the-enterprise/five-handy-mac-apps-for-net-admins/
(4) http://lifehacker.com/5857046/the-best-terminal-emulator-for-mac-os-x