The one thing that immediately comes to mind is Katie's super hero series of shorts.  Each one didn't just take my breath away, they incapacitated my mind's ability to function for several minutes and put me in complete and total shock.  (Reminds self he needs to analyze those shorts sometime. 

)
Some of Tolkien's poetry in 
The Adventures of Tom Bombadil and Other Verses from the Red Book come to mind.  Especially 
The Mewlips and 
The Hoard, but 
Shadow-bride and 
The Last Ship also come would fall into this category -- though to a lesser degree.
In Tolkien's 
The Children of Hu'rin the enormity of the tragedies that happen easily take my breath away.
There were a few books in the vast collection of Star Wars Literature that also placed a special spell on me, but time has erased the memories of their names.
I'm sure there are more, but they don't come to mind right now.  I'm going to have think this question over somemore. 

Cassandra Mimetes wrote:
Many small but clever plays on words awe me.
Me too. 

  Clever authors that pack a large amount of essence into their words, play on words, or hide foreshadowing inside a foreshadow's shadow go a long way towards stealling my breath. 
