MtGox USD....which might as well be fairy dust at the moment for how easy it is to get hands on it.
That said all other exchanges are on a serious up trend too, I'll be surprised if it breaks through the all time high in the next week or so without a large dump beforehand.
I agree, all USD asset get frozen on MtGox. Might as well turn it to whatever fiat that is legal to transfer to a bank, then convert it after to USD. By then, it's way lower then the MtGox price.