I agree that the XKCD "radiation" chart is an instance where an XKCD-style comic does a better job of explaining something than an equivalent well-written paragraph. But I don't agree that it's a particularly great visualization.
The "radiation doses combined" transition seemed fairly clear to me. In every case the collective doses are measured in the new SI-prefixed unit delineated by the scale on the left. If I were to criticize anything I would be a little more wary of the color choices and the box labeling. The = sign and parenthetic dose notation seems a little confused (the blue box dose size uses a different convention from the others).
While the chart could layout some things a little more clearly, I think that Minard's chart shows that one shouldn't reduce information content solely for the sake of simplicity.
It's clearly within Munroe's capability to make such a graphic; he did this one on a deadline. I'm not criticizing Munroe (though: not an XKCD fan), just making an objective assessment of the graphic.
And, like I said: here's a case where a graphic, even an imperfect one, probably communicates rich information more effectively than prose. Unlike the "relative sizes of data" infographic upthread.
Scale of the Universe, Radiation, IPv4 space, lakes & oceans, gravity wells, and Money all come to mind.
(You can curse me later).
[0] http://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=0...
By contrast, the infographic you like uses illustrations incorrectly; for instance, isn't it confusing the area and radius of circles? Notice how it uses multiple pictures each drawing a single comparison on a single axis. Think about how many words the same comparison takes in prose (not hard, because all those words are included in the infographic in gigantic type above the illustration, often in radioactive neon green).
--- Also: note that this [unfavorable] comparison is against a relatively weak example of explanatory illustration --- the best examples in _VDQA_ are way, way better than these NYT examples, which are a bit chartjunky themselves. If there's a good critique to be leveled at E.T., I think it may be that he tends to be overly favorable to friends, students, and, most importantly, people who share the same aesthetic sense that he does: simple line drawing style, low-saturation colors, arts & letters themes. Look at that "Game of Life" illustration, for instance; ouch.
Look at the "airspeed velocity of an unladen swallow" by, I believe, one of his students --- a truly excellent, effective example of an information graphic done in E.T.'s favored style [literally, with E.T.'s favorite palette]: