To the original poster...
I think the main point here is that there are many anti-virus solutiuons, and none are necessarily 100% effective... what one misses another one will catch and vice versa. However this is even true of expensive solutions such as Norton, Kaspersky, AVG Internet Security etc etc etc.
Basically - don't bother paying and install one of the many free ones we've discussed and you'll be about as protected as you can be! Use common sense when surfing and if you choose to visit "naughty" sites or download movies and stuff via illegal methods then expect to get in a mess at some point regardless of what internet protection you use
We can all give you our opinion (and that's all it is) on what is best to use - but none of us are right and none of us are wrong. It's a preference on what works for you. I trust the combination of the 2 free products I listed, but could I promise you 100% that you won't get a virus still? Nobody could.