Virus Scanning on gmail

Just logged into my gmail account and they now scan for virus's...This is one more reason to move the rest of my helsby.net emails to gmail. The only issue I have with gmailing my domain is that when I read the mail in thunderbird on the home pc, it doesn't mark the mail in gmail as read (which I wouldn't expect it to) but that means that gmail thinks I have loads of unread messages.
Update I've now made the switch and all mail that is not addressed directly to Kristen and I now goes via google - that'll give it some spam to think about :-)