Companies that succeed in tapping into massive market opportunities can lead to handsome gains for their shareholders. As an investor, ignoring the short-term noise and staying focused on the company's opportunity will help you succeed in building wealth in the stock market. This is the key to buy-and-hold investing.Three Fool.com contributors recently selected stocks they think could make rewarding buy-and-hold investments. If you have some cash -- say $3,000 -- available to invest that isn't needed to pay ...