Slytherin Values

Quote	Source
Or perhaps in Slytherin You'll make your real friends Those cunning folk use any means To achieve their ends.	Book 1, Page 118 Sorcerer's Stone, Chapter 7, "The Sorting Hat"
"You happen to have many qualities Salazar Slytherin prized in his hand-picked students." ... "Parseltongue - resourcefulness - determination - a certain disregard for rules," ...	Book 2, Page 333 Chamber of Secrets, Chapter 18, "Dobby's Reward"
And power-hungry Slytherin Loved those of great ambition.	Book 4, Page 177 Goblet of Fire, Chapter 12, "The Triwizard Tournament"
Said Slytherin, "We'll teach just those Whose ancestry is purest." ... For instance, Slytherin Took only pure-blood wizards Of great cunning, just like him	Book 5, Page 205 Order of the Phoenix, Chapter 11, "The Sorting Hat's New Song"
"I was Head of Slytherin," said Slughorn. ... "Still ... the prudent wizard keeps his head down in such times. All very well for Dumbledore to talk, but taking up a post at Hogwarts just now would be tantamount to declaring my public allegiance to the Order of the Phoenix! And while I'm sure they're very admirable and brave and all the rest of it, I don't personally fancy the mortaility rate - "	Book 6, Page 70, 72 Half-Blood Prince, Chapter 4, "Horace Slughorn"

List of those in Slytherin House from hp-lexicon