Just found out why my last.fm chart blog display kept screwing up.

When I inserted it as an Image widget, Blogger fixed the width and height at what the chart was at time of insertion. Since this is a dynamic, not a static image (it keeps changing), this screwed up the aspect ratio whenever the chart dimensions changed (as they do when songs with long artists/titles are played and then disappear).

Looks like inserting everything as "HTML/Javascript" widgets is the best way to go.