My favourite terminal emulator, Terminator.

No, it's not that killer robot from future we're talking about. Terminator is one of the coolest apps I have ever used on Linux. It's basically a nice terminal emulator, but what lies under surface is that, we can use it to open multiple terminals under the same window. This gives us many opportunities. To exemplify my statement, I am posting a screenshot of my own terminator installation:

Here you guys can see, I have opened three separate terminal windows in the same window. Of course, I have used the fullscreen window here. :)

So, what's the purpose of using Terminator instead of Konsole or Gnome-Terminal? The answer is simple, it gives us the ability to manage multiple terminals at the same time. Here are some reasons for which we should use Terminator:

• Terminator helps us to use multiple terminals. What's the benefit? Suppose you need to upgrade your system using 'sudo aptitude update && sudo aptitude upgrade'. At the same time, you need to have a new terminal open, so that you can chat with your buddies using weechat or irssi. That's when you require Terminator. On the left, you have everything required for system upgradation, and to the right, you're chatting right away with your buddies.
• Often, we need to cancel a running command from another terminal window. Terminaor can serve the purpose easily. For example, suppose we had previously issued the command "sudo aptitude upgrade" and the connection has somehow got terminated. It takes time before aptitude realizes that. ;) Just cancel the command from another window using "sudo pkill aptitude" and you're done. Having multiple terminals gives you the power and absolute control over your system.
• It's certainly cool to browse the manual entry for a command before running it. For the novice bash-programmers or casual users, Terminal can be a great help in learning BASH. What's the point? Just open a terminal for practising the commands, another for running "man <command>" before running it, and yet another for telling your buddies how you feel. :D
• For those like me who'd like to stick with their GUI rather than switching to some Tiling Manager such as ION3, or wm etc. terminator brings in a combination of the best of both. Your terminal is rightly tiled away, which you can still have your good ol' desktop breathing. 
• It's kinda geeky and cool to have terminator running, right? Your pals would just wanna say "Holy Heavens!" seeing that you're listening to your MP3s via mp3blaster or mplayer on one window, managing your system through another and taking some quick codes using VI or pico on yet another window. :D Endless possibilities.
• Terminator is lightweight, and runs freely on any Desktop environment.

So why waiting? The best way to understand an app is to give it a shot right away. After all, it's not windows, right? You can always get your app for free and remove it right away if you don't just like it. C'mon mate, you're da boss when it comes to your linux desktop, right.