Ok, my vote for the best AntiSpyware software is the terribly named SuperAntispyware product.
In my humble opinion it is the best antispyware program out there right now. Used best in conjunction with online scanners such as Ewido Online Scanner This is how I setup my computers for people. The reasons I call it the best?
1. It found rootkits and keyloggers not found by Symantec or AVG.
2. It has a free version, though the full version was on sale today for only $19.95!
3. Doesn't have a big or intruding presence in the GUI (No in your face begging)
4. System footprint (compared to others) is reasonable for the work it does.
5. Vundo removal without having to resort to other tools. (so far)
Try the free version first!