“Birthright, Part II” features almost none of the regular cast of TNG in an episode which kind of destroys the character of Worf. “Starship Mine” features all of the regular cast of TNG in an episode which almost destroys the Enterprise. Episode 129 of Trekabout destroys your boredom!
My favourite episode (so far at least) has to be The Best of Both Worlds. The stakes are huge, the characters get to fight something way beyond them and everything is basically perfectly executed. Fantastic episode(s)