Since I don't like to use an antivirus because I think they do more harm than viruses, I wouldn't install a resident shield. But, just in case a virus sneaks in when I download a file from a random website, I just downloaded ClamWinPortable (yes, I'm very much into portable apps these days, because they don't screw up Windows - mainly the Windows Registry and DLLs) so that I can run a check on a file that I download from a "untrusted" site MANUALLY (mainly cracks and patches). Only to make me feel better; not because I want to use an antivirus. I hate when virus guards check every file that you open/modify/read, when they are not infected (or even when they haven't been modified/created since the last scan) :S This is why I think a virus guard should be supported from the kernel, not as a 3rd party app running on a layer on top the kernel.