In my experience the only people that complained were ones that ran spyware supported applications such as Kazaa, Limewire, and other such software.
My short list is Adaware, Spybot, Cwshredder, Stinger and a pass of Housecall and to eject all they find in their stock settings. That usually gets most of it.
I recently tried spysweeper(webroot) upon advice from computer tech help, they said ad-aware causing hiccups, deleting something in windows syatem it shouldn't??? finding it a bit harder to get used to, any feedback would be great.