Kaspersky is great in the fact that it isn't a resource hog like Norton. However, Norton seems to stay updated more frequently. I use avast myself.
Kaspersky is the choice between the two.. as kaspersky ranks No.1, you can see anitvirus ranks in google search
Frankly I don't know why everyone seemed to like Kapersky and Norton is bloated software. Been very happy with AVG Free and not likely to change anytime soon.
kaspersky, no doubt about it... It scores 100 on 100 in terms of controlling Spaming, Virus Activities, Email Security, Lan Security... Excellent i use it from last 3 year...
i go for kaspersky.. FYI, kaspersky updated more frequently too.. my kaspersky update more than 5 times in 1 week as i noticed..