Photo-copy equipment maker Xerox ( XRX) may seem like a dinosaur in a world of digital documents, but a 2010 acquisition of Affiliated Computer Services for $6.4 billion gives Xerox exposure to a side of the business that has much more stability. ACS provides document management and business process outsourcing services under long-term contracts. The net result: Xerox's sales don't grow much, but it is a remarkably profitable business. Consider that Xerox generated more than $1 a share in free cash flow in 2011, with that figure expected to rise to $1.40 by 2013, according to Goldman Sachs. That means book value is likely to keep building at a solid pace. At some point -- soon -- investors are going to realize the disconnect between the current $7 stock price and book value which is in track to exceed $10 a share some time in 2013. To see these stocks in action, visit the Top 5 Bargains in the S&P 500 portfolio.