4. Nero - Star Trek (2009)
Nero, like Khan just before him, is a quotable dream. Everything he says has a snarling snap to it, which makes it fun to try and emulate him. He stands out, an overly emotional Romulan, who wants nothing more than to kill Spock for his involvement in his world's destruction. His intimidatingly large ship and its ability to travel through realities make Nero a bonafide threat to anyone and everyone.
3. Khan - Star Trek II: The Wrath Of Khan
When you look at the original Khan, you can't really judge him for his impact, or his grander aspirations because he failed. He really didn't do any harm to the grander scheme and of the characters who mattered, only Spock really died and it wasn't because of Khan directly. Yet, Khan is endlessly cool. The way Ricardo Montalban chews scenery is undeniably entertaining. He's one of those characters you just can't get enough of. He's beyond quotable and his overall look and vibe is iconic. It's so hard to judge anyone against Khan because he's so much fun to watch on screen. Still, he had a very little greater impact on the galaxy than others would later on.