What would it be? What would it's spec's be? What would it be made of? Any specific colours, patterns? Any ideal features and so on?
Maybe your dream knife already exists, if so, what one is it?
Personally, I like heavier knives, and I like channel construction. I'd get something made of a high-grade steel, perhaps with a Damascus blade. A Spring latch to keep the latch out of the way, zen pins, nice and long - maybe 5 inch handles. A nice, sexy sabre style blade, too. Weighing in at about 5 - 6 oz. Dark colouring, but not BK, something like a nice gunmetal or blued steel look.
That'd be my dream knife. How about yours?