I also think that a ban on the US bank accounts of MtGox is imminent. And this will almost certainly crash the price of Bitcoin. However, as you say that will not destroy Bitcoin. In fact it will make it stronger. However, people that have invested all their savings into Bitcoins, and worse who have actually over-leveraged themselves to purchase Bitcoins, will no doubt get hurt badly.
Just keep in mind that I (and probably the vast majority of people who have thrown their savings into bitcoins) are in this for the long run. The shutdown of mtgox no doubt would leave a huge hole in bitcoins, but in the long run i see bitcoin recovering and moving far beyond.
The biggest issue facing bitcoin, is that there's nothing to stop a "bitcoin 2" from entering the market.
A lot of people here are mining, trading and we're all happy as Larry that the price is going through the roof.
You think that this competitor will just come out of the blue? it has taken bitcoin over 2 YEARS to get to where it is today. Infact there already are talks of new systems being developed such as ripple:
http://forum.bitcoin.org/index.php?topic=3557.0 better yet, these systems just might merge to form an even better online currency.