You've gotten some very good advice so far. I would also say either Norton IS or Kaspersky IS. Which one? If you like things very simple: Norton. It's what I recommend to my non-geek friends. Very easy to use. Also, it fairly light on resources. If you are more geeky and have don't have a lightly powered machine, then KIS is likely more your speed.

Re: ESET, it's actually pretty good. However, back in Feb I had a problem uninstalling it. Neither ESET's uninstall tool (in Safe Mode) or AppRemover was able to uninstall it after ESET blacklisted the key that gave me a few days before.

Fortunately, had a done a partition image of my system drive prior to installing it. Otherwise I would have been forced to reinstall Windows. That experience has turned me off ESET.