Don't use a dash. While it doesn't make it harder to RANK at the very moment, it's a lot safer to use a non-dash domain with a modifier at the end.
If your keyword was Black Hat and that's taken, using Black Hat World is just as ok and even gives you a bit of flavor.
If you expand to podcasts, radio, TV or videocasts it's going to be a LOT harder for you to verbally give your URL.
Which of these sounds better:
"Visit us pumpkin dash carving"
"visit us at pumpkin carving central"
EDIT: Got flagged for URLs so my examples are a bit worse than before"
It's just a lot SAFER to use a non-dash domain with a modifier. You can't predict the future. Even if right now you don't want to use a podcast... what will happen when google announces it will weigh in heavily on backlinks from itunes? or what will happen when google's grizzly update penalizes domains with dashes? It might happen, but they will NEVER penalize domains with modifiers.
And what happens if you need some quick cash so you want to sell the site? Because of these future uncertainties and the difficulty to verbally say, you're going to have buyers that were wishing that you had branded differently and the buy-price might reflect that.