I don’t know what others are using to secure their family computers, but here are a couple utilities that I have installed on family machines:
Norton AntiVirus – I’ve used it for years, and haven’t found a reason to change. I don’t like Norton’s Internet Security, AntiSpam, or Firewall, but the AntiVirus is still perfect for me.
NetNanny 5.0 – I have this installed on all my kids’ machines. I really only use it to keep them for “accidentally” hitting sites that they shouldn’t. But for kids that spend too much time on the internet, it also has features to limit the amount of time they spend online.
Net Nanny’s Chat Monitor – this is also installed on my kids’ machines, but I don’t always have it turned on. It can do everything from log their chat sessions and email them to you, or just limit the amount of time they are chatting.
PestPatrol – This is my favorite spyware utility. There are other free ones out there, but I’ve been saved by this one many times, and it doesn’t require a ton of resources. There is a yearly subscription fee to keep it up to date, but since using this software I have totally eliminated spyware from my machines.