Excellent choice in free or shareware Spy??

Any good choices in freeware or shareware for Spyware detection?
I am using Adaware and McAfee, but wondering if there are others too.

 

Mix of free and pay not mentioned by the other posters:
AVG Anti-Spyware
CounterSpy
Spyware Doctor
SuperAntiSpyware

 

For real time active spyware protection, I also recommend Comodo's BOClean. Some other good free tools are:
Spyware Terminator http://www.majorgeeks.com/Spyware_Terminator_Without_Web_Security_Guard_d5242.html
Win Patrol http://www.majorgeeks.com/WinPatrol_d3380.html
Microsoft's Defender http://www.majorgeeks.com/Microsoft_Windows_Defender_d4466.html (some people say this isn't that great, but IMO it's ok)
Arovax Shield http://www.majorgeeks.com/Arovax_Shield_d4704.html
Browser Hijack Retaliator http://www.majorgeeks.com/Browser_Hijack_Retaliator_d4582.html
SpyCatcher Express http://www.tenebril.com/consumer/spyware/spycatcher-express.php

NOTE: You mentioned that you're running Adaware. While it is a great program for scanning and removing spyware/adware, It does NOT offer any real time active protection in the free version. They have a paid version for active protection, contact Lavasoft for more info http://www.lavasoft.com/

 

Thanks for everyone's input.
I very much appreciate it.