It would seem odd, to me, to see a random guy carrying a knife or gun on his belt. I'm not sure how I would feel about that. Nervous perhaps. The only people who openly carry knives around where I live are bikers.
Edit: A little research on local knife laws has been interesting. There are no restrictions on size or materials, but there are restrictions on type, purpose, and concealment. The knife has to have a utilitarian purpose.. carrying the knife for self-defense counts as a weapon which then makes it illegal.