Let's face it: blowing up a planet is just too civilized! It's too fast, and it's WAAAAAY too messy. Yes, the Xenoss are the scum of the galaxy and no one wants them in their glorious civilization. So by all means, scourge them from the galaxy. But what did the planet that they live on do to you? Nothing! That's a perfectly good planet down there. Therefore, I'd like to see some new ways to "planet-crack". Sure, a nanovirus that slowly renders every sentient, intelligent being on the planet down to a formless goo that's excellent for fertilizer might be slower, but it leaves the planet (and infrastructure!) intact for your superior race to make a brand new home on.