This visualization was featured on Nathan Yau's blog, Flowing Data, as part of a post entitled, "Years You Have Left to Live, Probably". It's not the MOST visually-striking piece out there, but I like some of its features. The visualization presents the probability of dying (okay, a little morbid) in multiple ways -- one by a circle tracing the probability curve of living to the next year -- the circle traces a portion of the curve and then bounces into a histogram below that grows as the simulation runs (seemingly fun, until you realize that each drop represents a death) -- and another by a simple numerical display of the probability of living X more years. Presenting multiple "angles" on the data means that the visualization requires some amount of parsing, but I think it leans towards being engaging rather than overcomplicated. Plus, viewers can use the gender drop-down menu and age slider to "personalize" the chart.
Yau used D3 to produce this visualization. He appears to have also written a custom script (simulate.js) to control the circle "drop-and-die" animation. His code is nicely commented, so it's relatively easy to see how he's building each piece, though there are several portions that I find unfamiliar and would probably need to play around with to fully understand its functionality.
Minor criticism: Yau has the luxury of posting to his own blog, so he has set the width of this chart to 1000+ pixels -- that is probably less than ideal in most settings. Also, the line representing the probability of living to the next year shows that the probability is 100% until age reaches 60ish. It's quite likely that the probability is 99.999%, but perhaps this bears annotation given the certainty expressed by 100%.