is definitely my favorite, w/ IoMD
in close second. I absolutely loved how they changed Enterprise's intro of the historical space exploration montage to an historical space conquering montage, as if it was being broadcast in the mirror universe that we were all living in. I thought it was a really nice touch. Parenthetically, I do believe we're actually living in the mirror universe right now, BTW.
And even though I really like DS9, I really never cared for their take on the MU.