Pop-up blocker? Feh. Ad server blocker. That's more like it.
I've got my
hosts file all set up with ad servers from around the world, all pointing to my own machine. Since most popups are generated by external javascripts
on adservers, I don't often see popups or popunders.
The few that do show up won't load the pages that are called, so they don't spawn other windows at all, which leaves them pretty easily closable -- especially due to my lightning-fast ALT+TAB CTRL+W reactions.
Now. If there's a site I'd like to support via toleration of adbanners, and I know they make money from the ads, I'll let those adservers (if not too wide-spread across the web) through by deleting them from my hosts file.
If an ad gets through from a site I don't wish to see ads on, I track down the server that's called and add it to my hosts file. Voila.
PM if you're interested in getting this set up and need more help than that link provides, or more servers to add to your file.