We are currently using Trend Micro for a large business 10,000+ It is satisfactory, and works well for networks. I do not think that it's worm remover tools, and virus database are as good as symantec's, but the AV itself works fine. It doesn't seem to use up too many system resources when in use, which is nice.

as for CA's software. I've heard good and bad about it. It's VERY customizable, much like the windows registry. But, their support in recent years seems to have dwindled. Symantec and Trend would probably top my list of medium to large businesses. and Symantec for small business. As for personal PC's. I recommend www.free-av.com It is an excelent free home AV, and is developed in Germany. I've never had a virus that infected my system so bad that it couldn't be removed with free-av. Updates are regular, and easy to install. I've not tried their pay version, but I suspect that it would work just as well if not better than the free version.

-The Rat.