New Additions to the main list:
Trend Micro PC-Cillian Online House Call - Online Virus Scan.
Panda Platinum 7 Anti-virus - Another good anti virus program that has 1 year of free updates.
Emisoft On Demand Trojan Scanner Another free on demand Trojan Scanner.
Spyware Blaster Another spyware removal tool. Free but I haven't tried it yet