Kaspersky is the best...I learnt it through a very hard expereince...recently my PC got infected by some virus while I was "Fully Protected" by Mcafee...I tried a lot of anti-virus programs...none of them able to do anything...they all scanned and said no potential threat...but even that moment the virus keeps opening hundreds of browser instances..I was sick and tired until my friend told me about kaspersky. I installed and "Bingo"..that virus which was troubling me was removed right away and it found nearly 10 more potentially unsafe programs..My computer works much much faster since then...peace of mind..finally...