I've been using <a href=http://security.kolla.de/">Spybot: Search and Destroy freeware ever since Mary Anne turned me on to it. Between that and a decent firewall (I've got Norton now, but I was using the freeware version of ZoneAlarm with no complaints, before...), I've got no complaints.

A.F.A.I.C., it's the best thing to come out of Germany since the Porsche... and how can you resist this:

I. Freeware
First of all, the reasons why Spybot-S&D is free:

I.a. Dedication
Spybot-S&D is dedicated to the most wonderful girl on earth :)

I.b. Binary
What do you get if you buy software? Lots of ones and zeros, nothing more. If they were distributed as art, I could understand paying it. But if the main goal of their order is to earn money - by fees or ads - I don't like it!

I.c. Conclusion
This means that I grant you the license to use Spybot-S&D as much as you like. But if you like it, I ask two things of you: say a prayer for me (and the most wonderful girl while you're at it ;) ) to your god - or whatever you believe - and wish us some luck.

The most pop-up-plagued site I go to regularly is Accuweather.com - between those two hunks of software, I only get what I ask for; nothing extra.