Got to have it - a day, a week or a month - but every single PC on the face of the planet should be rebuilt, from the BIOS up and then rebuilt with protection installed, updated, and running.
Yep, back-up your data - format the hard drive(s) - update the BIOS, reinstall your OS, install the three best anti-malware programs with most recent definitions, scan and then restore your data (and rescan, reboot, and re-scan). shouldn't take more than a week for the entire world to accomplish this feat.
I say - September 2009 - should be the target date for this global month of restoration.
Why? Why? Why?
Bots, zombies, adware, spyware, malware, bugs, bytes, virus and flies.
OK, forget about the flies, but all the others apply.
Maybe, just to throw the black hats off - we just do this thing starting tomorrow. All the world kills their zombies and bots tomorow at 12 noon UTC!