Some examples of doublespeak, with etymologies:
http://en.wikipedia.org/wiki/Doublespeak

collateral damage?
gosh darn that phrase has whipped up some ire online, my favourite however, is the changing of war to defense
http://www.yourdictionary.com/library/drlang008.html
http://www.riprense.com/collateral_lingo_damage.htm
http://carmen.artsci.washington.edu/propaganda/bland.htm

**edit**
SO has just suggested the fiendish changing of buy to own. Sneaky b******s