my investing / speculating philosophy in a nutshell:
Buy some of everything, tinker at the margins.
I hold US stocks (primarily ETFS), large dividend-paying individual stocks, cash, gold, real estate (both REITS and investment property), foreign stock index ETFS (EAFE, Japan, Hong Kong), Short _Dollar ETF (UDN), etc.
Then depending on conditions I tinker at the margins. For example, I decreased my US stock allocation from about 75% 2 years ago to about 55% today. And have more dividend-paying defensive stocks. Also, have about 20% Cash waiting for buying opportunities.
Using a diversified approach guarantees that I will at least be partly wrong at any given time. However, it also guarantees that I won’t be completely wrong, and more likely to make money with lower volitility.
This approach is boring, but it got me through the late 90’s speculative bubble and through the 2000-2003 bear market without losing my A$$.