The Darksteel set is everything you loved about Mirrodin and more: more equipment, more artifacts, more abilities, and even more cards. Darksteel is the first "small" Magic expansion to release with 165 cards. Among them, you'll find artifacts that are indestructible--which means just what it says: destruction effects don't send them to the graveyard. And if its an indestructible creature, damage won't do the job, either.
The only things getting broken here are rules.
Arm yourself with Darksteel.
The Darksteel expansion includes randomly inserted foil-finished premium cards in a limited, 165 all-new, black-bordered card set.