Buying at the top of a bubble would sure suck. But then again it could go to $20,000/oz. Gold is pure speculation and fear driven. The gold bubble has burst more than once and it can happen again - like in the 80's.
But IMO if you're investing this much in gold then you're betting against civilization. You're betting on a global disaster. And if that happened I think buying a house in the country and storing food and guns would be more important.
If you think the USA is going down I'd suggest diversifying into a country house, 10+ yr food supply, guns, ammo, other supplies, then a USD cash stash, then gold and silver coins.
If you buy gold and silver ETFs now you're simply gambling.. and that may or may not pay off. Enjoy trying to time the market.
But if you do invest in gold then you get to be one of the millions of gold-investors now cheering for the collapse of the USD. They now have a vested interest in the collapse of their own country. With any luck you'll make it happen by self-fulfilling-prophecy. Enjoy a gold backed currency when the gold supply is controlled by other countries often hostile to the US.
Watch "The Secret of Oz"
The Secret of Oz (the revised Money Masters) (download torrent) - TPB