With all due respect to EHOF and his excellent post, the one thing I disagree with is I strongly recommend placing money conservatively as investment that average a gain of 10% per year make often make more money than aggressive investments making an average gain of 20% per year. The principle if called Preservation of Capitol. Here's an example...
In a highly aggressive investment yields go way up and way down. Let's say you have $100,000 invested in year one. The first year the investment drops 40%, not unusual for aggressive investing. Now, the $100,000 is $60,000. The next year it gains 80%. You now have, after year 2 a total investment of $108,000 and an average yield of 20%.
Now, look at a conservative investment designed to conserve your money. Take the same base year investment of $100,000 and let's say in year #1 the fund gains 10%. You now have $110,000. If the fund gains 10% again in year two, you now have a total of $121,000 with an average yield of only 10%. After two years you have in the fund averaging 10% $13,000 more than the one averaging 20%.
And right now, with Obama-economics, this is a difficult time to be in a risky/aggressive fund.