ASICs wont come in all at once. There will be no crash. Even if they did came out at once, the two-time increase in mining (to ~7000 coins per day) until the difficulty adjusted would be completely dominated by the current demand for coins (daily buy volume at gox - 100k btc which is like 15 times higher than everything miners could sell).
So sorry, no ASIC-induced crash. Crash still possible, but for different reasons.
Besides, the miners will just buy more ASICs, which only take bitcoins anyway (at least the only one seen in the wild).