I like Kaspersky's antivirus product - I received a free student version during my OU course and I have been using it ever since. It costs about $30 a year (I think) but it doesn't seem to affect my computer's performance one bit, apart from bombing me out from my games if it decides to run an update at that time. It has integrated Internet security, which is always catching dangerous scripts for me. It also has an antivirus warning sound that appears to be the hiss of the creatures from Aliens. It nearly made me jump out of my seat when I first heard it!