I've been using Kaspersky for a few months now and I'm pretty satisfied with it.
But, a friend told me that Kapersky has a trojan in itself. It was said to them in seminar that he attended.
And, after awhile you'll notice some files missing. Well, I haven't experienced my files missing yet. So, I don't know if that is true.
But since my license will be over soon, I might try Avira or AVG since they're free and I've been reading pretty good comments about them.

Agree with all about Norton slowing the computer down. You can try AVG--free and seems to do a great job.

I am using NOD32 for my computer from last 3 years and its been doing the best for me. Currently i am using NOD32 5 the latest version. It never slow down your pc speed and give the best performance. I would also suggest you guys to go for it as its the best.

Try NOD32 i have also its key for ten year validity.

Well i am using NOD32 and i found it best.