Ad Annihilator

There are also options to block specific ads and pop-ups from the right-click menu in Internet Explorer.

But you need a warning: Unlike other set-and-forget ad blockers, Ad Annihilator is a geeky tool and you'll need some spare time to configure it perfectly. Ad Annihilator works with any version of Windows, but only with Internet Explorer (5.0 and newer). After the 15-day trial, you're going to have to pony up $30 to keep using Ad Annihilator.

--Steve Bass