McAfee is what I use on my desktop, while I use AVG 7 free edition on my laptop (haven't upgraded to 8 as it won't let me install it >_<)
My advice would be to stay away from norton like the plague.... Its easily the worst security system ever, and AVG free edition is much better. If you are prepared to shell out the money for a full anti-virus, I wouldn't recommend McAfee... While it works fine for me, it's now considered one of the top of the range protection suites..... Still, it's your choice... have a look at reviews and see what you think
