You can forget the BX unless you get the kind with an equipment grounding conductor in it, the Fed's will require this.
I usually use MC for concealed work & EMT (with an equipment ground pulled in) for exposed work.
I'd say forget the ENT, knowing how mine inspectors think, they probably wouldn't care to see it.
For circuits up to #6 AWG, your equipment ground must be sized 100% of the hot conductor, #4 & up it must be at least 50% of the hot conductor. This could be a problem if you tried to run any cable larger than #10, since the equipment ground will be too small.
What state will this be in?
Tom
