Pretty much any of the lines used by Agrias or Thundergod Cid during their Orbonne Monestary fights qualify in my book.

"Seven shadows cast, seven fates foretold. Yet at the end of the broken path lies death, and death alone!"

"Open your eyes to the darkness, and drown in its loveless embrace. The gods will not be watching."

I even enjoy Cid's rumbling, intrigued "Show me more..." Though, after his fight got nerfed into the floor, I can only imagine him disappointedly muttering, "Show me less..."