So what this potentially means that if bitcoins keep the newcomer demand high, and the supply falls, there will be a great rise in the bitcoin price on a daily basis. And in just 10 years from now, 1 bitcoin could be worth 10k or more (a bit optimistic).
If bitcoin demand grows, the price will grow. If it doesn't (market is saturated), then price stops growing.
With more than 50% coins already mined and quite low annual inflation (12% in 2013 comparing to 50% in 2011), supply does not affect prices much (in 2011 if you remember the price was slowly going down as miners were steadily selling their coins). Today demand is defining the price much more.
If we are doing optimistic estimation, it depends on the target market. If Bitcoin takes half of gold market as a distributed ledger of wealth, then its price has to be more than 10-20K USD. If it takes 10% of the global black market (estimated size is 1800 bln USD), its price must be around 8000 USD per BTC. Choose your market and figure how much BTC must be worth if it's used on X% of that market. If BTC replaces all currencies on global scale, each BTC would be much more than 1 million of today's dollars. I believe this can happen, but it may take a generation or two.