What most people tend to miss is that all relative nominal prices are arbitrary. In other words, the fact that commodities today cost more nominal currency that they did 30 years ago doesn't scare people as much as bitcoin is currently rising. But if bitcoins are expensive, people will demand more work for bitcoin or less bitcoin for work.
True, the market is growing, and hasn't reached it's highest potential saturation yet apparently. I, among many here believe that it will blow way further. The one advantage fiat has over bitcoin is that it is a smoother transition because it is enforced in one go on an entire population. Bitcoin can't offer that luxury. However, when the bitcoin economy saturates, it's prices will be inherently more stable than recklessly minted fiat. Fiat money has a tendency to overshoot inflation (and many times even hyper inflate). Except with bitcoin the tendency is more stable, and reversed, which clearly the better direction (unless you are a proponent of systematic theft). When saturated, the bitcoin monetary base will represent more or less the value of all goods traded with it, which is exactly what minting fiat is supposed to achieve and fails. Considering how people today have to adjust prices to a constantly devalued currency, I don't see why we couldn't deal with it when bitcoin stabilizes.
Besides, if changing prices worry us, lets think of new-age methods for measuring inflation/deflation rates that can be applied to bitcoin. So far most people/systems get these measured for their fiat from extremely biased sources (those who print the money) with stuff like the CPI.
Edit: it's worth looking at this related topic:
https://bitcointalk.org/index.php?topic=142877.0;all