Anduril - Thank you for your skepticism. We all need to remember that forums are supposed to facilitate discussion. As a minority community attempting to demonstrate the benefits associated with BTC adoption we should always be honing our arguments and solidifying our opinions.
That said, I have been thinking that hoarding is a big problem. But, have you heard about the event that occurred on April 4, 2011? Supposedly 30,000 BTC were sold over a short period of time. Considering that the supply of BTC was just over 5 million, this is an extreme amount. Indeed, a transaction of this size did have some control over the market - we saw the USD/BTC drop considerably. However, soon after the ratio adjusted back to its original level. This indicates resilience in BTC itself and maturity in the BTC community. For this reason I'm encouraged that hoarding isn't the biggest problem that BTC faces.
Furthermore, you're right in being concerned with the liquidity of BTC. In many capacities this goes hand-in-hand with the hoarding problem. Several things are certain, however: As more people accept BTC in exchange for goods and services, the more likely others will follow, the price will become less volatile, and the more liquid it will be.