I have a Dell XPS, which came with McAfee. I almost took a new subscription, when I learned that McAfee isn't what it used to be. Now I use Bitdefender Total Security 2013, it does a good job. Besides antivirus, it has firewall, basic tuneup, encryption, ... It has also theftprotection with location service, lock and nuke function.
Once a year I run the Tune Up Utilities trail to thoroughly remove redudant clutter. Each year a new version is released with a 15-day trail.
Another tool I use is Shields Up!, Gibson Research Corp, to check if my homenetwork is stealthed and firewall settings secure.