Notably, if you cast Murder targeting your opponent's Mirrorwing Dragon, your creatures will each get a Murder, not your opponent's
They're still kicking about Standard as well (thanks to Foundations , which has a lot of staple goblins), and are likely to make a huge impact once Lorwyn drops
This puts it slightly lower than Draco, but relevant for Modern and Pioneer for decks that care about mana values on cards
Its also somewhere in the discussion for Stifle-naught style decks, which specialize in playing creatures with hideous ETBs and canceling the triggers
Her Phyrexian horrors get bigger and bigger the longer she goes unchecked, and you often have to expend so many resources getting rid of her that it costs you the game
This isn't limited to spells