In case you haven’t heard elsewhere, there’s a nifty unpatched vulnerability for Internet Explorer floating around. And it’s actively being exploited. Metasploit, an exploit toolkit used by penetration testers and script kiddies alike, is able to detect and utilize it.
Under these circumstances, Microsoft has been known to rush out a patch before the next scheduled Patch Tuesday, but the Christmas and New Year’s holidays will obviously slow things down.
In the meantime, installing Firefox and/or Chrome is prudent. I have and use both, since, to my knowledge, there hasn’t been a time yet when both of the two most popular alternative browsers had unpatched exploits in the wild.