"Since getting home, I have avoided installing an antivirus, and have never been infected"

How do you know that you do not have a virus??? If it's a date triggered virus or one of the latest email viruses, you probably wouldn't be able to tell until it was too late and after you infected everyone else you know.

We remove about 20 or so viruses per month, it seems as though over the past few years viruses are easier to get, primarily due to the internet.

I personally favor Norton AntiVirus, I haven't used McAffee since Win95b (McAffee's screen scan would screw up with open gl screen savers, or the system would hang on boot up... so i developed an attitude)