This is a question that many retires struggle with. Unfortunately, there is no one size fits all answer to this question, especially when you are married or have an ex-spouse that you were married to for at least 10 years (being married for 10 years allows you to collect social security on your spouse's earnings record). Which is why a customized analysis should be performed based on your particular circumstances (something that we do at Inner Circle Platinum Advisors LLC for clients). However, social security should be properly viewed as an immediate annuity that is indexed for inflation, and if you are married it pays out for 2 lives (the two lives even applies to ex-spouses with 10 years of marriage before divorce).
This article on smart money is about delaying social security and explains how waiting is the same as buying an immediate annuity whose pricing can't be matched by private insurance companies- though I would disagree with the author's assessment that social security offers such a good deal because it isn't worried about profits, doesn't need to market and uses a "fairer" life expectancy table. Social security is mispricing their benefits because 1. they don't change pricing based on sex, 2. they don't change pricing based on prevailing interest rates, 3. they don't base pricing based on the life expectancy or health of the recipient. So the product is mispriced, being especially beneficial to women, married people and the healthy. This comes at taxpayer expense- an insurance company couldn't do this because it would go bankrupt. This is good for the recipient because they can take advantage of the benefit (and one should!) but it is bad for the system in general.