I would say "The Cat" is right.
The more persons that uses Bitcoin the more coin's will be lost.
The time between finding new Bitcoins is getting longer and longer. And they do not replace the lost ones they are just generated.
So if Bitcoins becomes a every man/woman thing. Then the value of a single Bitcoin will raise to something insane before it will just die because the number of persons actually having coins will be to small to function as a currency.