[Methadrine]

Some serious misconceptions in this thread.. that I won't bother to fix or comment on.

Anyway, for Windows you should get Avast or AVG (Avast is slightly better at updating their virus database) since they're both free. Avoid Nortons products at all costs. They're clunky and too invasive. Also get spybot S&D for adware etc.

For the mac: get Little Snitch (costs money but worth every dime) as the firewall Apple provides is rather crappy (ofcourse, you could always install the great and venerable PF but that needs manual configuration that most people don't grasp) If you run a virtualization product and/or recieve a lot of Windows-aimed things in your email that you pass on to others, get clamAV (also used by Apple themselves in their server edition of OS X) so you can atleast scan them and not propagate any virii they may contain to your friends and co-workers.

And for Ben: Get Windows 7 if your computer can run it. It's fathomably better than Vista and is actually the first Windows I bought myself since it was actually worth the cost and is pretty much rock-stable. Vista 64 got better though, run it on a workstation at work and everything we threw at it works.

As for myself, I went mac and will never return to Windows. For me, my Mac Pro is the dream machine and it serves my needs well.