My MacBook Pro
This is my personal laptop. Every now and then i install the free Norton AntiVirus provided by my service provider to clean it up a little and then uninstall the Antivirus a few days later. I know i run the risk of getting a worm but the risk is much lower than Windows
My ThinkPad
THis is the laptop i use for work. Has Norton installed. I'm sure it gets attacked by worms but i have the notofocations turned off
My Dell Optiplex
This is a desktop PC i keep at home and it serves as a storage server to automatically backup the data on all my other computers. Once my laptops are n my network they automatically backup their data to it. Also serves as a media server for my phone and XBox. That one has Norton and a couple of other tools loaded. Notifications are on so i see quite a bit of alerts. Mind you, I do NOT use that PC for browsing at all. I often see hack attempts coming from the outside. WHen I trace their IP addresses it always ends up being from another country.