I think Avast! is the best Anti-Virus. It is very light. It does not slow down your system at all. It is almost like i am not using any Anti-Virus software
Actually Avast is about the third heaviest AV out there. AVT rated it a 13 on system drag. KIS is a pig as well at 14. Only Lavasoft at 16 is worse, and that one nearly kills systems - doubling program load times in some cases.
But Avast is pretty much bloatware these days. Why are you here posting this disinfo anyway?