I had two memorable moments, first was when Atreides and Harkonnen nuked almost their entire armies with shield/lasgun reaction during epic final battle for Arrakeen and i looked at them and said "Dune heals itself, bi-la kaifa" and (as Fremen) just waltzed in last turn and won the game.

Second when again Atreides vs Harkonnen and Atreides player held Yueh traitor card so he was absolutely sure Yueh can't be traitor. It was Jessica, Thufir vindicated.

Do you have all expansions? There's some wild stuff there, Ixians with movable fortress doing spice grabs, Tleilaxu rapidly becoming my second favourite faction after Fremen, Choam with at first seeming minor mechanics which will make you swim in spice in no time, Richese with their own treachery minidec they can keep or sell, Ecaz simulating other factions perks and Moritani with traps (including susprise nukes). 3rd expansion (Ecaz/Moritani) also have some cool new mechanics like nexus cards for usage when you're not in alliance and homeworlds for each faction (2 for Emperor) which gives additional bonuses and can be invaded adding next strategical layer.