Uh oh, you're not going to want to hear this...
but my ISP does indeed filter out all virus mail
on the server end.  I receive nothing but a
message saying that the message has been
quarantined, and the name of the sender in case I
want to contact them.  I also have an up-to-date
virus checker on my own system, of course, but it
hasn't found a single infected email since the
mail system started pre-checking for us.

You may want to have your ISP's technical guru
contact Speakeasy's (http://www.speakeasy.net/) to
see what sort of solution they've implemented, if
you're interested in offering the same sort of
protection on your own service.  I find it quite
reassuring to have the extra layer of defense,
actually.  :)

But now, with that out of the way, I have to say
that anybody who owns a computer and
doesn't have their own virus software,
whether or not they think their ISP is filtering
emails, is a fool and a half.  Email is hardly the
only way to get a virus, and this guy was
positively inviting infection by not taking
responsibility for his own protection.

Wow, I sound like a condom ad.  O_o  It's true,
though.

Anyway, in his honor, I would like to present my
favorite anime idiot, in a recreation of how you
must have looked when he tried to pawn the
aforementioned responsibility off on your service
(you're Lina here ;)