I expect there will be people who reply to this comment to argue it should be "E-T-C" or "Et Cetera". You can ignore those people; they probably say "exclamation mark" instead of "bang".
This is one of those "jif" v. "gif" holy war issues. (Maybe "etc" is a minor skirmish rather than a full blown war.)
Now, if Dennis told you it was pronounced etsy, you would have a point.
If you look up "etc unix pronounciation", while there is a lot of bickering, I still think "etsy" is the slight majority among old timers. I will admit that this usage seems to have faded.
I spent some time trying to find video of any of the original Bell Labs Unix team actually saying the directory out loud--I couldn't find any. I'm going to keep searching, but they honestly seem to go out of their way to avoid it. I did find some fascinating videos along the way [1].
To my chagrin, there are a few oblique text references on the web that say indicate that within Bell Labs, it was pronounced "etcetera". But I'd still like a canonical reference.
[1] Like this video from 1982, including Kernighan, Thompson, Ritchie, and Aho. http://youtu.be/tc4ROCJYbm0