Stocks are the best-performing assets over the long term, and investors can gain exposure to every U.S. stock through the Vanguard Total Stock Market ETF (NYSEMKT: VTI). Just stashing money in a bank account or under the pillow won't provide enough return to survive in retirement -- today's 7.9% inflation rate underscores this fact. Benjamin Graham, the famed investor who taught Warren Buffett, once said: "In the short run, the market is like a voting machine -- tallying up which firms are popular and unpopular.