SiteMeter code used to be a culprit for a while. Incompatible philosophies concerning child containers (Microsoft Knowledge Base) were the microscopic reasons behind other crashes. The Microsoft guys thought that the error was fixed in Internet Explorer 8 except that it returned soon.
The most recent villain was Google Friend Connect, a gadget I used to have in the sidebar, much like many other blogger.com blogs. People in Google who are responsible for their side of the bug have admitted the bug.
According to preliminary tests, the fixes of MSIE and/or Visual Basic that Microsoft released yesterday (July 28th: KB 972260, 973923, 973924) have repaired the bug - or at least most of it. Try to click the Google Friend Connect link above. Does it crash your MSIE? Well, sometimes you get a non-fatal "overflow" error but the newest tests I did seem to be flawless. Maybe it is the Google guys who fixed it, and the MS updates accidentally appeared on the same day.
I will still leave the gadget on a special page because crashing the browser for all IE users would just too big a hassle for me to cause. Update: No, after a few more tests, I have boldly returned the gadget to the sidebar.