Hugh telling "Locutus" off in "I, Borg."
I especially love the way Hugh seems to have to force himself to say "not", as if he can hardly bring himself to say something that is such an anathema to his entire former worldview.
Worf snapping Weyoun's neck.
Adolescent Spock throwing the Klingons around like ragdolls on the Genesis planet.
The Hirogen hunter tackling
his prey - a member of Species 8472.
Picard ramming the Scimitar. "He wants to look me in the eye." And the "Oh, crap" look on Shinzon's face when he realizes what Picard is about to do.
"I cannot defeat this Klingon. I can only kill him, and that no longer holds my interest."