I can't think of a good reason to throw a knife. That killing a person by throwing a knife at them only works in the movies IMO. Plus once you throw it you've lost a valuable weapon if you don't have another on you.
get a good set of hibben knives. not the cheap ones with his name stamped on them, but real ones. use those for practice. then check out colt, cold steel, and sog. i prefer darts, but hey, im a ninja.......