Proxomitron. It will get rid of window load and unload pop-ups, but it will let the ones that you want to go through (link pop-ups, mostly). It will also remove ads from pages without messing up the layout, and disables cookie snooping. If a site doesn't work with the filters, you can bypass them on a site-by-site basis.
I use Popup killer in Xp, excellent stops ANY popup window, and if you want top see the popup just hold down ctrl, it's only about 67k as well. You can get it from www.download.com just do a search for popup and files less than 100k in size