OCIR, I've used Norton products since Peter Norton was selling them out of his garage in Venice Beach. That doesn't mean I've always been an avid fan; in fact Symantec has just barely emerged from the "hate 'em" category after several years of bloated, intrusive products that seemed always to be in your face with unnecessary reports, buttons, and other forms of self-promotion.
However, just thought I'd pass along the fact that the 2009 version is MUCH improved on both counts. It's significantly better-performing and (if you spend a few minutes setting options to shut it the **** up!) less intrusive.
Finally, though, consider that it still comes out on top in most head-to-head comparisons of efficacy at trapping threats. I know a fair number of people who use other products - some started as a kind of anti-Symantec protest like the anti-Microsoft movement that fuelled Linux. Only one of them has been infected through his AVG antivirus, but I've heard of others with other products. In well over a decade (including two careless teenagers on our home office network) we've never been infected with anything through Norton.
We are using Vista 64 here too.
