Windows anti-Virus software

This seems to be an essential part of life in the windows world.

The University of Arizona makes available a package called Sophos to the university community.

The IT staff here at the observatory used to recommend Kaspersky antivirus software, but now Sophos is what everyone uses.

People used to recommend McAfee and Norton, but now these seem to have turned into viruses in their own right. The cure is as bad as the disease! They try to nickle and dime you and latch themselves into your system -- avoid them like the plague.

Someone "in the know" recommended Trend Micro for antivirus software, but I have no experience with this.