While pondering my options after the attack I mentioned to a friend the incident, and this person said: "Hey - Google has a malware/evil website for reporting such nonsense." Sure enough, Google does indeed have a site to report malicious software delivered by websites, and the form is quite simple: just enter the URL, enter a CAPTCHA code, and briefly explain the nature of the malware problem.
I am not sure about the effectiveness of the tool to date, but keep this in mind the next time some malevolent site designer tries to jack your computer.