Is there really ever a perfect title?
I think so. Though I think they're comparatively rare.
"A Hole in the World," for instance, was the perfect title for that episode of Angel. "Chosen" was the perfect title for Buffy the Vampire Slayer's series finale, and Buffy the Vampire Slayer was itself the perfect title for that series.
M. Butterfly is the perfect title for David Henry Hwang's play. Rent is the perfect title for Jonathan Larson's musical. The Persecution and Assassination of Jean-Paul Marat as Performed by the Inmates of the Asylum of Charenton Under the Direction of the Marquis de Sade is the perfect title for the bizarre play by Peter Weiss. Jesus Christ Superstar is the perfect title for Lloyd Webber and Rice's musical.
"Inter Arma Enim Silent Leges" is the perfect title for the DS9 episode. "Where No Man Has Gone Before" would have been the perfect title for almost any TOS episode other than the one it was applied to. "The Best of Both Worlds" really was the perfect title for the TNG episode, as was "Chains of Command." "Emissary" was perfect for the DS9 opener, given the dual nature of Sisko's role as both emissary of the Federation to Bajor and Emissary of the Prophets. "These Are the Voyages...," whatever else its faults, really did have the perfect title for what everyone thought might be the last episode of any Star Trek series for a very long time. "The Undiscovered Country" would have been the perfect title for Star Trek II.