I waded into the Social Security fray last week, but as your many worthwhile comments (36 and counting) show, there's a lot more to discuss.
On its face, the decision about when to take Social Security benefits might seem to revolve around longevity: Take them sooner if you're not healthy; wait if you're healthy and both your parents lived into their 90s.
But needless to say, forecasting your own life expectancy is a crap shoot. Moreover, there are plenty of other complicating factors to consider, such as whether you have a spouse, his or her age and level of earnings, and how long you plan to continue working. Throw in additional questions about potential changes in Social Security and future tax rates, and you've got a real mess on your hands.