Another vote for NOD32 - comes out tops on virus detection on the
Virus Bullentin, and its great on resources.
Its actually the AV software that Microsoft use to scan their stuff, so you know its got to be good! Also they provide regular updates, so you are covered pretty much as soon as viruses are discovered.
Of course its all a matter of preference. Many people like the simplicity of Norton, I prefer the safety of NOD32
