Living out in the sticks, being a very simple individual, and not really having much worth stealing... security ain't too big a worry of mine.
However, for ya'll city folk six's advice here is golden. I'd just like to add to the safe browsing... you could have the best possible anti-virus on your computer, but if you're going to unsafe sites or using unsafe programs it's only a matter of time before you get an infection. I know I'll receive a ton of flak for this here but I'd advise staying away from peer-to-peer file sharing programs unless you're a networking/security pro that knows how to clean crap up. Easily 98% of all the infected computers I work on have some form of peer-to-peer file sharing program like limewire or frostwire on them.
If you know what you're doing then they can be relatively safe programs. That eliminates easily 90%+ of the PC Users out there.
Not an expert on security and don't know how to clean your computer up if it get's crap on it, then don't use those programs. Stay away from any site claiming free crap, and in general just use a little common sense. If some dude walked up to you holding the keys to a brand new lambo and said to you "Hey! Ya'll just won the Malaysia lottery! Here's our complimentary car for you as a token of our sincerity. We'll just need your account information to deposit the money to your checking account!" Would you really trust him? If you say yes, you deserve what happens to you next.
Good thread Six.