There is a new vulnerability that was publicized recently, attacking the Windows Metafile format, which is used to display images. This can break your machine or cause malicious software to be installed just by visiting a website. Nasty.
This is a very important problem to fix immediately, as there are a large number of exploits out there already.
And then think about buying a Mac or using Linux.
Update: Microsoft has fixed the flaw for XP, but not for some of the older versions of Windows.Â Hopefully they will figure out that not everyone upgrades…