I use AntiVir Premium Edition, it falls into the category of hassle free and low resources and it updates itself (unlike the AntiVir free version
). I believe its detection rate is among the best. The license is 20 euros a year which is about £13.50.
Also, if anyone has tried the AntiVir free version and noticed the slow downloads for updates, the paid-for version has its own servers which are fast and reliable.

Also, if anyone has tried the AntiVir free version and noticed the slow downloads for updates, the paid-for version has its own servers which are fast and reliable.