The only thing that will kill BTC are the hoarders who sit on more than 500 BTC hoping to just cash out. Spend your BTC on businesses that will, in turn, encourage more to accept BTC. If you won't spend it, give it to me and I will.
More particularly, buy drugs off of Silk Road with your BTC. Drugs are a great store of value, they have a long shelf-life, and are easily convertible. You'll be building the bitcoin economy and be able to hoard to your heart's desire!