Worst missed opportunity in a classic line - Data's final line

I agree that the line was inappropriate, but your suggestion is just corny.
Perhaps he could've said "Resistance is futile?" in a questioning manner, before destroying the tank.

Read my reviews at www.alexfalzon.com

I always took that line as a mocking gesture than anything else.

The line works fine in the context. As in it would have been futile for the Borg to have resisted Data at that exact point in time and it is obviously meant in a mocking ironic fashion. Your alternative would have worked fine but would have been tonally different, more defiant and hopeful where as the line they used was more mocking or triumphant.

*Typical Data quizzical expression*

"Resistance is surprisingly effective."

He could have used an old Armold line and said "Let off some steam"

But I always took it as he was telling the Borg that he was about to win, and their resistance was futile. That he was using their own words against them, and how does it feel now, b*tch?

What's even worse, is the fact that Star Trek had to lower itself to the level of cool one-liners.

He should have said, "In case of emergency, punch glass."

Or "Have you noticed your boobs are really starting to firm up?"

Or "Oh S***!"

I've always thought it might have been better for him to have said it in Picard's voice. From the very beginning, Data was able to imitate other voices, including that of his captain and friend. My idea is, his intent was, in addition to ending the threat, one of vengeance: "You assimilated my friend, and now I am going to end you, and you can't stop me." It's still a good scene, though.