how should I invest my money ?

I am nearly 40yo and trying to work out how
best I should be investing my money.

[worried]

I started out mostly poor I have always held a conservative
‘saver’ type of mentality. I find the level to which people
live in credit debt shocking and am of the doom & gloom
opinion that the world of credit liquidity will turn sour
in the coming years.

I have approximately USD$150K that I’d like to invest,
but I am not sure what I should invest it in …

I have reasonable money invested in the following:
-own my home
-domestic and international stocks, bonds and REITs
-cash in money markets and term deposits
-numismatic rare coins

I am also considering the following investments:
-buying some gold bullion, if the price of gold returns
to around USD$500 an ounce
-would like to buy another home, but feel that Aussie real
estate is overpriced and will likely drop further.

I’d be interested in hearing opinions of any seasoned investors,
about any general investment areas they think I should consider.

Or should I just stick with the approx. 5% interest on cash ?

thanks in advance,
Martin.