Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

What is the best asset allocation for a retirement portfolio, and why?
It's all about risk. These guidelines were all developed based on the risk characteristics of the various asset categories. Bonds are ultra-low-risk, large caps are low-risk (you don't see most big stocks like Coca-Cola going anywhere soon), foreign stocks are medium-risk (subject to additional political risk and currency risk, especially so in developing markets) and small-caps are higher risk (more to gain, but more likely to go out of business).  Moreover, the risks of different asset classes tend to balance each other out some. When stocks fall, bonds typically rise (the recent credit crunch being a notable but temporary exception) as people flock to safety or as the Fed adjusts interest rates. When stocks soar, bonds don't look as attractive, and interest rates may rise (a bummer when you already own the bonds). Is the US economy stumbling with the dollar in the dumps, while the rest of the world passes us by? Your foreign holdings will be worth more in dollar terms. If you'd like to work alternative asset classes (real estate, gold and other commodities, etc) into your mix, consider their risk characteristics, and what will make them go up and down. A good asset allocation should limit the amount of 'down' that can happen all at once; the more conservative the allocation needs to be, the less 'down' is possible (at the expense of the 'up'). .... As for what risks you are willing to take, that will depend on your position in life, and what risks you are presently are exposed to (including: your job, how stable your company is and whether it could fold or do layoffs in a recession like this one, whether you're married, whether you have kids, where you live). For instance, if you're a realtor by trade, you should probably avoid investing too much in real estate or it'll be a double-whammy if the market crashes. A good financial advisor can discuss these matters with you in detail.