I would like to know whether a Great White Shark or a Killer Whale
would win in a fight. Any instances where this can be documented would
be great as well.

Joel

Hi joel1357!

Thanks for the fascinating question. :-)

The answer to your question seems to be that the killer whale would
likely end up the victor in such a titanic struggle.

There actually was such a battle videotaped in 1997. Seems that the
killer whale won quite handily. Accounts of this event can be found
at:

Clash of the titans: Whale vs. Shark
http://www.cnn.com/EARTH/9710/08/whale.vs.shark/

Peter Pyle's First Hand Account of Killer Whale / White Shark
Encounter
http://www.flmnh.ufl.edu/fish/Sharks/InNews/peterpyle.htm

I also found several sites that listed the killer whale as the only
know predator of great whites (other than other great whites).

Nigel's Wild, Wild Shark Week
http://dsc.discovery.com/convergence/sharkweek2001/ask/ask.html
Quote: "The above paragraph suggests, by definition, that great whites
have very few natural enemies. The only other sea creature that can
downright physically overcome great whites is the killer whale. Killer
whales grow considerably larger than great whites."

Great White Shark
http://www.wwf.org.uk/core/wildlife/fs_0000000020.asp
Quote: "The Great White Shark has only one known natural enemy with
which it competes - the killer whale or orca."

What do other people think? The following online discussion seems to
support my belief:

Great White Vs Killer Whale
http://pub18.ezboard.com/fsharks77551sharkattacks.showMessage?topicID=26.topic

I hope this information helps to set your mind at rest. 

If you need any clarification of the information I have provided,
please ask using the Clarification feature and provide me with
additional details as to what you are looking for. As well, please
allow me to provide you with clarification(s) *before* you rate this
answer.
                 
Thank you.                  
                 
websearcher-ga                 
                 
Search Strategy (on Google):     

"great white shark" "killer whale"
://www.google.com/search?hl=en&ie=ISO-8859-1&q=%22great+white+shark%22+%22killer+whale%22

No need for clarification, I am extremely pleased with your answer.

Thanks,
Joel