Depending on how much fluctuation you are willing to accept I would seek out some undervalued companies.
Consider AHT in the hotel business. At its current price and annual earnings, the company is buying back about 35% of its common shares every year (since the stock price fell so badly during the real estate crash). This means that every year the company is becoming 50% more valuable on a per share basis. Why 50% and not 35%? Because if you buy back half of a company's shares (50%) each share doubles in value (100% return). So i'd look into that for sure.
BP is also a cheap stock. Nobody is sure how much the total cost of the spill and lawsuits will amount to be, but most estimates put it in a range of $20-$30 billion. That's a lot of money! However that's also about how much BP can earn in 1 year. So if you assume that you could earn 15% in one year investing someplace else, then you should reduce the value of BP's shares by 15% to make up for the 1 year's worth of dividends and earnings BP will have to spend. However the stock price is down 36% since the spill, over-reaction? The company has hinted that dividends should resume in early 2011. At the current price you would be looking at a very large yield along with some great potential for growth as oil prices rise over the next 20 years. Do your due diligence.
There are still a few undervalued companies out there for sure. If you don't like wide swings in your account value and want to avoid uncertainty, stick to utilities like NEE or consumer staples like KMB or WMT. Their earnings, revenues, dividends, and theoretically stock prices ought to be able to grow relatively consistently over 20 years or so. Their stock prices aren't ridiculously cheap though, so don't expect huge returns.