I found two very interesting bits of information from the graphs in Brian Krebs' article, BLADE: Hacking Away at Drive-By Downloads
The first, I think we all recognize; that being IE6 is far more susceptible to drive-by downloads than other browsers. I was not, however, expecting the numbers for IE7 to be as high as shown in the graph.
The second point is the information provided by the BLADE group of the vulnerable applications that were most targeted in the drive-by attacks, with Adobe and Oracle SunJava far exceeding the figures of IE.
The lesson from this information is obvious, and one members of the security community have been harping at for a long time: Microsoft security updates are only one piece of the puzzle. It is also critical that other software be kept up to date as well.