MSIE is "too dangerous for routine use" according to many observers. Notably, one security hole allows malcious code to install itself on a user's system upon visiting certain web sites, without the user's knowledge.
Even the US Computer Emergency Readines Team (US-CERT) advocates a switch:
Use a different web browser: There are a number of significant vulnerabilities in technologies relating to the IE domain/zone security model, the DHTML object model, MIME type determination, and ActiveX. It is possible to reduce exposure to these vulnerabilities by using a different web browser. Such a decision may, however, reduce the functionality of sites that require IE-specific features such as DHTML, VBScript, and ActiveX. Note that using a different web browser will not remove IE from a Windows system, and other programs may invoke IE, the WebBrowser ActiveX control, or the HTML rendering engine (MSHTML). It is possible for a different browser on a Windows system to invoke IE to handle MHTML protocol URLs.