Antivirus can be a controversial subject. If you ask 20 different computer entusiasts or IT professionals what the best AV product is, you will not only get 20 different answers, but almost as many angry shouts about how horrible everybody else's picks were. Similarly, and only to make matters worse, if you do your research and read the "10 best antivirus products of 2011" articles then you will see that the rankings change all the time. Every year it seems some "who-the-heck-is-that" antivirus product makes it on to the number 1 or 2 spot for the major roundups. More frustrating is the fact that from site to site and review to review, the conclusions can be schizophrenic--with one site's number 1 pick being the other site's worst of the crop. From my own experience, I will tell you that no antivirus is a silver bullet, they all will catch some malware that others miss, and vice versa. Beware of fanboys and beware too of haters. But most of all, beware of anyone who gives you their opinion based on a "story", be it sad or happy. The 1 star reviews angry because they got a rootkit and the glowing reviews saying they've been happily using Antivirus 2010 since forever and have never had a problem.
There's your qualification and sobriety check. Now, here's my measured opinion. I'm a long time Norton user that first came across Kaspersky a few years back when Norton products were getting worse every year. Norton saved themselves with a fabulous 2010 release (and a 2011 to rival it), but Kaspersky who was once a dark horse antivirus no one had heard of has stuck around and made a name for itself. It's a good product and I don't hesitate to recommend it. I often recommend Kaspersky in business environments, but this is more due to the superiority of their Server Administration Kit than their AV Engine itself. Still, their AV consistently ranks among the best, and no I don't care where they happen to fall out of the top 10 in a given year. Try not to get caught up in the horse race there, as there simply is no good objective way to quantifiably say one AV is better at protecting you than another. I've found their protection to be solid and reliable and among the best out there, but you can drive the world's safest car and still get killed in an accident. Kaspersky 2012 is easy to install and configure and doesn't seem to have as many potentially perplexing options as Norton does deep in its bowels. 2012 is not especially efficient (Norton 2011 and Eset's Nod32 seem to have much smaller footprints), but Kaspersky does have a nice Gamer mode that can be flipped on when you want to play games. I've found Kaspersky has difficulty installing on systems previously inhabited (I would say infected, but then my own biases would show) by AVG or Macafee, but that is as much the fault of those products as it is their fault, and its a common problem for one AV to interfere with the installation of another, even after it's "uninstalled". I find that Kaspersky is one of the quietest AV products I've used and doesn't nag you the way many products tend to do.
All in all, there are lots of decent AV products out there, some of them free, but there's only 3 I would wholeheartedly endorse with my personal and professional reputation on the line and Kaspersky is one of them.