went to the wired.com website and got hit with over 100 pop-ups in less than 30 seconds.
http://everythingisnt.com/hosts.html
— install this text file onto your computer, it works on any computer (including handhelds) that use the hosts file for local DNS lookup (Windows, Mac, PocketPC, Unix, Linux, etc.)
What it does is block advertising sites by redirecting it to an empty port on your computer. Most popups are blocked, most ads are blocked, most malicious websites are blocked. Drudge Report with zero popups, zero ads - with no program running on your computer. I love it.
I didn't get any. I run Pop-up stopper on top of Firefox. It's free - scroll down to 'free tools'. http://www.panicware.com/
In addition to Pop-Up blocker, you probably want to run Flashblocker as well. Cookie Safe is another good addition for your Firefox.