With Berkshire Hathaway Inc. (NYSE: BRK.B ) 's annual shareholder meeting almost upon us, I am reminded of this investing gem Warren Buffett once said: "Only buy something that you'd be perfectly happy to hold if the market shut down for ten years." That bit of advice is beautiful in its simplicity. Buffett is challenging us to think long-term with every investment decision. That is a challenge we should all accept; constructing ten year portfolios that would make the Oracle of Omaha proud.