Actually, I think the discussion has split into two different areas:
1) danger from external attack, and
2) danger while browsing.
#1 first, as it's easier: A good antivirus, and more important, a good firewall. We've pretty well covered that in the thread so far. At home, we haven't had a successful attack in years, because we're pretty well buttoned up with Zonealarm and Avast.
#2: This is more complicated, although not too much so. Again, we have been in pretty good shape for a very long time.
First, a "good" browser. There are several. I avoid IExplorer, and even my workplace has made FireFox available to us (you could have floored me with a feather when they did, because they loooove their MS!). At home, we use FireFox exclusively.
However, that's just the foundation. The default options are pretty good for security, but go to Tools/Options/Security if you want to try different settings.
Next, I immediately go to Tools/Add-ons, and add three addons:
Very simple interface, it stays on the status bar. Left-click to select "block cookies globally", then any page where cookies are desirable (such as a place I go to all the time, http://www.texaschlforum.com
-- you may have heard of it
), a left-click will bring up the option "allow texaschlforum.com" (which allows it to place the cookie that is created when you check "remember me" at signon).
This inhibits FlashPlayer from working, allowing me to push a button when I want the flash on the page to play (I rarely do). More for avoiding annoyance than anything else.
This is one I just started using; it searches for, reports on, and (if you tell it to) erases Flash cookies at close of the browser. These are the scariest, since these are the ones which can track and report your browsing. The first time I used it, it found 64 flash cookies!
Firewalls and virus checkers will not
protect you while browsing. That requires the combination of a good (open-source) browser and just a couple of tools.
ETClarify: Virus and spyware checkers will
protect you after