Anyone that knows me knows that I don’t care having antivirus on my PC since most of the time you know how virus get into your computer. Network?, flash drive? or whatsoever. If it’s severe one, there is always a separate tool to check and kill it. That’s the way I choose.
However, with some of my wrack nerving clients, they just prefer to have something make them feel more secure although that’s slow them down. Most of the time, I recommend free one such as AVG, Comodo, etc. These anti-viruses works pretty well according to many people, but after a while, I still have to do cleaning up all infected PC with all free or paid tool installed. What the heck? What do they do really? Don’t they have recent virus signature? I don’t know. Signature/definition update issue might be one of them.
Recently I found our that Panda Could Antivirus, it’s still BETA last time I check, and it will likely to be free. What distinguish this antivirus from others is they loading definition on-the-fly while scanning. I am not sure if they send some info to the server for scanning or just downloading new signature, but it works to me. This can kill the hidden virus that Comodo Antivirus (installed) can’t in only 1st times of full scan. I don’t think they do on-access stuff which is good, no waste resource. You can just go do full scan once in a while. That should do the trick.
It, nonetheless, has a cons as well. It does take forever at 99%, but it is known issue and should be fixed in next release. Go check it out! at Panda Cloud Antivirus
ps. I still stop it all the time on my system unless I really want to scan anything =) This way works for me. It left only 1MB or so while turning off and about the same while on, but will consume like regular apps (20MB+) while scanning =)
added 2009-05-15: my worst fear happened. Panda deleted almost any of my tools, e.g. Cain and Abel and all kind of that stuff -_- darn it. That's why I never like having Antivirus on my machine :'(