Sorry, but I must differ here. I have *never* yet dropped any creature with the Death spell. "Finger of Death" works a lot better (7th level Mage), if that's what you're thinking of, but the 6th level Death spell never works for me; by the time I get it, the opponents are so tough they withstand it.
Maybe I'm using it on the wrong ones (I *know* not to use it on undead, so don't go there!)

or at the wrong times, but I've pretty well chucked it as a useless spell. There's far better ones out there, IMO, that do the job more efficiently.
-Sazerac