Which is the best antivirus?

Right from the date I bought my computer, i have been using NOD 32 Antivirus. This antivirus has been my best for the past 4 years and i had no problems whatsoever i do in the internet. But, recently i used tunnelling software to make torrents work in my computer as torrenting is blocked by my LAN administrator. Along with the seeds and peers, it also brought me harmful Trojans and worms. NOD 32 was great in detecting those Trojans but it couldn’t clean up the infections. I don’t know why my best antivirus, infact the world’s 3rd best antivirus couldn’t clean the infection. So, i had no other choice than to try another antivirus to clean up my system. I decided to try with Kaspersky antivirus. But to my disappointment, Kaspersky also couldn’t clean that Trojan. I had no other way to format my system. But, i was very much impressed with Kaspersky as it scanned my entire computer in no time and also it blocked a lot of intrusions from my network. I thought i would try kaspersky for some time in my system and now, after a month my computer is still virus free even after some hefty torrenting. Kaspersky really rocks. But still, NOD 32 is my favourite antivirus as it has kept my system secure for 4 years!!!