To avoid potential catastrophes, I use different browers and settings based on the situation. This way it's unlikely that a scripting exploit or corruption I encounter can access, modify or propagate much data.

I use Firefox for all my work-related internet stuff, Safari for serious personal things, Opera for almost everything else. Opera lets me easily turn on and off javascript/plugins/etc on a per-site basis (right click -> Edit Site Preferences).

It was 6% Jan. 2007 http://www.w3schools.com/browsers/browsers_stats.asp