I really like the idea, but I have a question about how transaction growth can be sustained once all 21MM bitcoins have been generated. In order to support borrowing/lending IMO you need an increasing supply of currency. Otherwise where will the interest on debt come from? The only other type of non-inflating "currency system" I can think of is the market for collectibles (baseball cards, limited edition artwork, etc…
Intrinsic value - FALLACY! Behold, the Subjective Theory of Value - http://en.wikipedia.org/wiki/Subjective_theory_of_value
Concerned about long-term viability of bitcoins? Maybe your concern should be with learning logic and economics first.