I've used Norton's and Macafee both are junk in my opinion. I liked PC-cillian but when it expired I tried AVG and I think it is good and the price is right. I have been using the free version
I was a big fan of AVG A/V before the current version (8). The current version has added so much clutter, I can't recommend it anymore unless you are willing to take special steps during the install process, and only install the free (or paid) A/V product, not the free suite.
I'd have to look up the special command line arguments for the install again. I can't remember them offhand.
Without the special arguments at install time, you end up with link scanners and toolbars attached to your web browsers. And there's more crud if you don't do a custom install and disable all the other options.
I'm running it one of my PCs, and with these precautions, it's still a decent product. Without them, it's starting to become more Norton-like. (Slow, bloated and includes extra things that you don't need.)
If you are willing to pay for it, eset nod32 is probably the best option. If you aren't willing to pay for it, doing a custom install of AVG 8 A/V free with the special instructions is not a bad way to go. The last alternative would be a different free product or installing AVG 8 A/V in the normal manner. (There might be a better free product now, I don't really know.)
-David