Proxomitron is an excellent pop-up blocker - and much more. Have used
it for years and really love the way it filters out ads, flashing
text, animated gifs and much more. The web is a much nicer place when
you use this.
I've only got one problem. After installing Sygate firewall I
discovered it does not work properly with Proxomitron. For now, I've
removed Proxomitron from my start-up folder and am looking for an
alternative blocker - but I miss it so much I might actually end up
uninstalling Sygate instead.