Smoke 'em if you got 'em. Unless the landlord says "no way!"

My application to rent a house was denied because I’m a smoker. Doesn’t that violate fair-housing laws?

Not so much. If the landlord consistently says "no way" to smokers, he can refuse to lease to you. Federal fair-housing laws are not, surprisingly, to protect your right to burn carcinogens wherever you please. They're about making it illegal to deny people housing base of their race, color, sex, national origin, religion, handicap or familial status. 

Want to know more about fair housing laws? Check this out.