If you loved the terminal window accessibility found in Quake, then you'll surely love Visor. It provides a system-wide, hotkey-enabled terminal window that you can access no matter what you're doing. Hitting one button will result to a terminal window sliding from the top of your screen. If you think that's cool pick up this app, which is now on v1.2.1, where the "Choose File" button has been fixed. Visor is compatible with Quartz 10.4 and higher.

Download: [Visor v1.2.1]