Antivirus, Anti-Spyware, Anti-Malware

Antivirus Comparison Firms

1. Virus Bulletin
2. AV Comparitives
3. AV-Test

NOTE: TrendMicro is on my permanent blacklist for their lawsuit against Barracuda over the later's use of ClamAV.

Windows

ESET NOD32 The best AV at any price. If you are going to pay, don't even think of buying anything else.

Free Options

Avira AntiVir® PersonalEdition Classic - Good antivirus, no spyware protection.

Avast! Antivirus Home Edition Free for non-commercial home use.

AVG Anti-Virus Free Edition, Anti-Spyware Free Edition, Anti-Rootkit Free - Need to download/install all 3 products.

Spybot Search & Destroy - The greatest Anti-Spyware at any price.

MacOSX/Linux

Free Options

ClamAV - Commandline. Mostly for e-mail filtering.

[ClamXav for OSX. - Neat graphical interface. Uses the ClamAV engine, gets defs from main ClamAV project directly.