Ouch, hopefully doesn't turn into blaster 2.0. These days you're just asking for trouble if port 80 is open and you don't have a need for it, though.
[0] http://en.wikipedia.org/wiki/Blaster_%28computer_worm%29
[1] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2003-0352