Awww ... now I feel bad since @Delia's suggestion is by far the best in my opinion! Anything that could cause a crash could be taken as Armageddon and thus would easily be the most powerful miracle/spell.
The miracle of life is pretty powerful as well, but I think there is a nicer one, a smaller one ...
My general answer would have been all
mind control miracles!
Perhaps
bloodlust falls into that category, but my favourite one right now is
rdrink:
Picture this!
EvilSatho speaks in sathospeak: "Your puny and worthless god!"
HappyCleric responds in goodspeak: "Taniel commands you to drink from my hands now. Obey, EvilSatho!"
Your deity grants you the power of 'drinking'.
You spread your arms wide, spinning around in a full circle as you bring
your hands together to form a small bowl. As Taniel's power is unleashed,
water forms in the air above your cupped hands pouring down to fill them.
EvilSatho drinks thirstily from your cupped hands.
Of course this is extremely
contrived. I just think the picture of a large Satho drinking thirstily and irresistibly from her hands would be kind of ... cute to see. Especially considering that halflings are quite small, and the EvilSatho may find it difficult to drink from cupped hands!
PS: I am kidding here of course.

Best race: halflings.