I disagree with previous posts. "The Die Is Cast" is just as strong if not better than "Improbabale Cause." "The Die Is Cast" gave us a payoff...finally! Not just talk of war but actual repercussions as well as plots put into motion. There is not a wasted scene and the direction is brilliant (the final scene stands for me as the most inspired bit filming in the history of Trek. The Dominion is shown to be a truly worthy Trek villain, one that got the best of the enemy in a way that no foe on Trek had ever done so before, making them officially the best bad guys to appear on the scene since the Borg. Its level of dialogue was not quite at the level of "Improbabale Cause" but it was still crackling with energy and purpose. Besides the legitamately thrilling action and justified fireworks made up for any drop on the dialogue front. Not to mention it expanded the boundaries of "Improbable Cuase" from the more intimate focus of two mysterious men talking about galactical conspiracies while in small rooms to the more grand approach of actual epic betrayals and defeat of major military powers of the galaxy. Instead of just talking about the blood that could be spilled (which Trek during the TNG era unfortunately did a bit too much), this episode showed you the blood being spilled. The results of this episode shifted much of the balance of power in the AQ and initiated storylines that would carry the show during its final seasons. As I wrote before in many ways it did for DS9 what "Coming of Shadows" did for B5.
"Improbabale Cuase" is marvellous, without question. But The Die Is Cause is just a bit better. Tain's words to Garak at the end seem sad and chilling (astonishing just to se the fall of this great military mind). The torture scenes between Odo and Garak provided more heartpounding moments than anything we got in "Improbable Cause." Odo's remarks about wanting to return home is an important revelation that you could not find in the previous ep. The decloacking of the Romulan and Cardassian ships around DS9 just before they entered the wormhole was one of the greatest opening teasers that the show ever had.Sisko's defiance of an order from Starfleet was much needed and overdue for the character IMO. The added bonus of the use of Michael Eddington wasn't bad either. The look of dread and horror on Tain and Garak's faces as they realized they had walked into a trap. The revelation of Luvok being a changeling was actually a legitimate surprise. The Definat being granted arguably its most kick-ass moment ever on screen. "You know what the sad part is? I'm actually a very good tailor." You folks are telling me that that's not a classic piece of work?
What is so amazing about "Improbabale Cause" is how it manages to be so great despite being a script written at the last minute to make the story a two-parter. Still that being said the main purpose of that episode was as filler and it at times show with its numerous running dialouge scenes between Odo and Garak. But The Die Is Cast is about consequences.
Anyway, I voted fo "The Die Is Cast", "Improbabale Cause" and "The Search Part One (part two was awful). I have a soft spot for "Explorers" and a strong liking for "Destiny" (which really got the Emissary story-line up and running again) "The Abandoned", "The Adversary", "Facets", "Through The Looking Glass", "Past Tense", "Defiant", "Second Skin", "Civil Defense".
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I didn't vote for Past Tense because I didn't want to use up two options for that and also didn't want to cheat. 
