Recent warnings by the French and German governments have highlighted concerns about the security of Internet Explorer, for example see http://news.bbc.co.uk/1/hi/technology/8465038.stm . This has led to recommendations that users should abandon the use of Internet Explorer.
However is this good advice? Clearly in the short term, yes. Until Microsoft release a security patch for the existing problem it clearly makes sense to avoid using it, and particularly IE6. In this longer term though, I think it is unwise to assume that Internet Explorer is necessarily less secure than the alternatives. The fact is that attackers target IE because of its popularity - why would they bother to target a browser that hardly anyone uses? Those responsible for malware are generally in it for the prospect of a financial return, and it is common sense for them to target the most popular browser. Joomla has faced much the same problem in the Content Management world.
If the current scare results in a substantial exodus towards other browsers then we can certainly expect to see more attacks targeted at them in the future. For example, there are already security issues concerning some of the add-ons available for Firefox - see http://www.sciencetext.com/remove-firefox-addons-improve-security.html.
If the result of this current scare is to finally bury IE6 then I don't think that there will be any web developers shedding a tear, it will make web development so much easier. It really is the most annoying web browser going, and it is astonishing that so many people still apparently use it.