The two I use. Both will also take out Trojans. For daily use I use SUPER and once a week I use the heavy hitter, Spybot to get rid of anything SUPER missed.

SUPERAntispSpyware free edition:
http://www.superantispyware.com/download.html

Spybot Seach and Destroy:
http://www.download.com/Spybot-Sear...4-10122137.html

Be very careful of clones with very similar sounding names to Spybot Search and Destroy, so download from above only.