A friend of mine has a Saluki (hers in photo here):
which according to wiki:
"In 1996, The Guinness Book of Records listed a Saluki as being the fastest dog, capable of reaching a speed of 68.8 km/h (42.8 mph)."
Despite being bred for raw speed they're an affable and reserved dog, not that rambunctious and apparently somewhat easier to care for than some more common breeds. Sometimes ribcage is easily seen thru the skin like the dog is starving but I'm told that's normal in healthy Salukis.