Sometimes you just know. As soon as the Borg showed up in the second season of "Star Trek: The Next Generation", it was clear they were a foe unlike anything else we'd encountered on the final frontier. Sure, they dressed like they'd just stepped out of a PG-friendly fetish club, but their utilitarian cubic ships, all-for-one hive mind, and awesome arsenal ensured that — within the space of a single episode ("Q Who") — they'd catapulted themselves into the A-list of Trek's rogues' gallery. They didn't even have to say or do very much to get there.
A year later, they assimilated Jean-Luc Picard in "The Best of Both Worlds" and more than justified the hype to become the Enterprise's most powerful and chilling enemy. It was a status they retained until they were downgraded into villains-for-hire in "Voyager".
