Of course. Pie charts look natural and easy to comprehend when visualizing things like market share of certain products, for example browser market share (http://www.netmarketshare.com/browser-market-share.aspx?qpri...). In fact I'd argue that that's a much better representation than a bar chart, like http://www.w3counter.com/globalstats.php, because the former makes it easier to comprehend roughly what proportion of the total market each browser represents, which is not as straightforward to see in a bar chart (in bar chart it's only easy to see how different browser market shares compare to each other). So yes, pie charts may be appropriate at times, although I agree that it's a poor choice in this particular case, as the root comment explains.

How about a stacked single-bar chart? I'd suggest that it has all of the benefits of a pie chart without introducing perception issues of angles and areas.

Well, I guess you could make a fat bar and still run into problems... Ah, visualisation!

This pie chart -- http://www.youthblog.org/pie%20chart2.jpg -- is accurate and presents the data better than any alternative.

(so no one has to click blindly, it's a photo of a pie showing how much of it was eaten or not)

Whenever the data to be displayed is most easily conceived of as a proportion of a whole. If all of your data points added together equals the population you're sampling, then a pie chart might be appropriate.