I carry mine in my pocket - no case, no pouch - along with everything else that's in my pocket. I understand that Tony Bose finds the fussiness of carrying his knives in a pouch or case to be somewhat amusing - I think his comment was "I make pocket knives, not pouch knives". Heh.

A lot depends on what the handles are -- if they're bone, stag, or micarta, I'd carry it. With ivory, it would depend on just how solid it is - I would NOT carry most bark ivory, but I would carry quality interior ivory (in fact, one of the real problems with ivory is that people don't carry and use it -- ivory requires oils and moisture to remain in top condition, and carry and use supply those automatically). I personally would not carry a pearl handled knife -- I consider it just too fragile -- but there are those that carry them without problems and say they're actually fairly durable, so YMMV.