Quick Anti-Virus Guide 06.2012
I've used the following:
Norton Anti-Virus--->loved the early versions, however quality declined and the software got more and more bloated. Didn't protect well since 2003 when they did a major code change. This code change redid the scanning and it got more lenient.
McAfee Antivirus--->always had a bad vibe and I had it on my laptop and it would be a CPU hog as well as high on memory usage and I still got infected.
Sophos AntiVirus--->very low profile Ui and very low memory usage for both consumer and server editions. It's occasionally overprotective... but that's a good thing. it has given me issues with a couple lock ups but I haven't had that problem much lately.
Moon Secure--->Ok for a backup and nothing much more. Kept crashing a lot. You get what you paid for and it was free.
Panda Cloud--->Free for consumer and paid for server/pro version. Pretty good for a free one, however it was supposed to offload processing to the cloud and it still used a lot of local power to run it and perform it's actions and it would often have the media center PCs fans going loud and we got it specifically to keep the usage down, as we used it as a media pc and we need as low profile on BG usage as possible! only recommended if you don't care about my circumstance above.