Stop Terminal from Making Irritating Noise

As you fellow devs can imagine, one of the most irritating things I experience in my daily programming life is this silly noise that Terminal makes every time I enter an invalid key. I've went to System Prefs and turned off all sounds for notifications and yet this same stupid noise that terminal makes keeps on inundating me with notifications that I have entered an invalid key sequence.

Any way of stopping this or is Terminal conspiring against me.

From Terminal.app's preferences (Terminal menu -> Preferences), go to the "Profile" tab in the top pane, make sure your profile is selected, then click the "Advanced" tab in the right-hand pane. Under the section "Bell" there's an option for "Audible bell" which you should deselect. There's also an option for "Visible bell", which is a very useful alternative.