Spybot has been around for one hell of a long time. I remember using it in conjunction with Ad-Aware SE years back. I'll be curious to see how successful the NEXT version is... it does look like a well deserved face lift!
I was actually nominated to be an MVP when MS News was on NNTP as I was one of the first to recognize running the two along with other stuff worked with a good A/V in protecting your O/S.