know what i'm doing or not, i prefer to run one.. it's nice to be able to open any random email attachement and feel 99% safe that it will be stopped if it has a virus in it. suit yourself, but i'm never too good for safe guards that will save me time (ie, prevent me from possible having to reload my whole syste).
that being said, I would have to cast my vote for Norton's AntiVirus.. it rules.