Aliens are coming... which do you prefer?

I'd pick #4, because if all it takes is to hit them with Slim Whitman's "Indian Love Call" song to take 'em out, then it's a no-brainer.

#1, The Kanamits might work... if we could convince them that pigs taste better than humans, but that's a big gamble.

Of course, the introduction of complete order by #2, The Borg, might not be so bad considering how terrible humanity is at being civilized with itself. But then there's that matter of freedom of choice. And who wants to be dependent upon plugging yourself into machinery at the end of every day? No thanks!

#3 and #5 are just too nasty dangerous.

#6? Well, maybe we could get used to Raktajino (Klingon coffee) or blood wine, but dying for your honor at the drop of a hat on even the most ridiculously minute misconstruing of disrespect... not worth being enslaved by the Klingon Empire.