Can sound be off every time I power off? I would like to config my Mac (10.8.5) to turn the sound off every time I power it off so that when I power it back on it is silent and doesn't produce that funny boot sound.  Can that be done?

The thing is, I come in to work late and, if I had the sound on before I turned the laptop off (e.g. watched YouTube at home) and forgot to turn the sound off before, my whole cube farm at work resonates and they are like "this guy just came in to work"...  LOL
You can set the audio value on boot using this:

sudo nvram SystemAudioVolume=%00


00 will set to 0% volume (i.e. mute)

You can reset this by resetting the NVRAM by booting with ⌘⌥PR, or running

sudo nvram -d SystemAudioVolume