I've tried six different antispyware programs picked two
I currently use Webroot's Spysweeper AND Spybot Search & Destroy. Spysweeper has gradually but perceptibly improved its quality, number of spywares detected and its user interface. There's still the clunkiness of having to download manually a new version and install it, but the updates to databases are automatic. Spybot S&D is much clunkier but still occasionally catches a few items that Spysweeper misses. I like its Immunize function.
When I first installed Spysweeper and ran it, I found over 180 spyware program or items in my machine and when I removed them all, there was an obvious increase in the speed of my computer.