Debate the Bolivian Army Ending all you want, but Avon, surrounded with no escape possible, raising his gun and smiling in defiance, is one badass moment.
One for Vila: arriving on the bridge of the Liberator to find that Avon has killed the invading soldiers (a moment of awesome for Avon himself) but been knocked unconscious in the process, Vila bluffs Servalan into thinking they're going to kill her and successfully drives her off despite the fact that the Liberator is perilously low on power, Avon is semiconscious, Cally, ORAC, Tarrant, and Dayna have all been kidnapped offship, and they are essentially helpless.
The Series two Finale. Just... watch it.
Orac and Vila forcing a gigantic brain to go into meltdown with various knock knock jokes.
Servalan playing the crew like a piano in Gold, getting precisely what she wants and completely screwing them over in the process.
"City at the Edge of the World" is Vila's CMOA. He's the hero and the romantic lead. Avon even defends him to a bullying Tarrant (though Vila isn't in the room at the time).
A small moment in "The Keeper" showcases why Servalan is such a powerful character. After the loud and hammy Shal of the Goths demands that she visit him in his tent, not the other way around, she simply shakes her head — "M-mh" — and breezes off.
Avon letting himself get captured, knowing he'd be tortured by some of the most proficient and sadistic torturers of the Federation, and lasting five days without even giving up his name, all to find and get revenge on the man who tortured Anna Grant to death.