About thirty-four people have now inadvertently sent me e-mail containing the W32.Badtrans.B@mm virus, some of them sending 5 or 10 infected, infectious messages. None of 'em got to me, and I can understand how anyone can accidentally contract a virus. (I got one myself, last year) But I suspect some of these time bombs were disseminated because their unwilling victims did not go to a rather small expense of time and money. You may be willing to run the risk of infection but most trojans are now written to not only contaminate you but to plunge into your address book and e-mail themselves to all your friends. So running a good virus protection program on your computer is a matter of simple courtesy to others.
No virus checker can catch them all. The one I got last year infected me before any of the anti-virus companies had heard of it. But most of the ones that make the rounds could be caught by McAfee VirusScan or Norton AntiVirus. If you won't do it for yourself, do it for your cyber-buddies. (I use McAfee ActiveShield, which is for folks with an "always-on" DSL or cable modem connection to the Internet.)