My webserver uses clamAV ...open source, free from most "features" and beats major AV companies to protection 77% of the time
http://www.linuxpipeline.com/166400446 (also has a wintel port)

At work My desktops use SAV corporate 10...mostly ok and easy to administer

At home I use a suite of tools provided by my cable company actually the F-Secure suite and I like it pretty much certainly didn't require the reformat of my HD like Norton home 2005 did... (not -ever - going to go with symantec home av software again)


HOWEVER... AV and most spyware scanners are retroactive protection... (edit:to clarify... av is retroactive because you need to wait for def's to be pushed...)

I've fallen for Blink from eEye as an intrustion -prevention- system. Blink happily denies virtually all (or maybe -all-) zero days, phishing scams, buffer overflows and most anything else for my webserver, AD and file servers and desktops. Features include a spyware scanner that found things that 5 other scanners did not, a vulnerability assessment tool, application and system firewall...it's an IPS not an IDS...detection is too late...prevention is where it's at...

http://www.eeye.com/html/products/blink/index.html

and it's bloody cheap $59.00 US per machine..(with my users...that's priceless)