Security

Anti-virus

Bitdefender Free

Great if you want a strong, silent, and free antivirus solution

Avast

Expect great all-around protection against viruses and trojans.

Avira AntiVir Personal

Lightweight and solid. Good ratings

Firewall

Comodo

Anti-spyware

Superantispyware

Malwarebytes' Anti-Malware

Encryption

Truecrypt

Disk encryption software. Encrypt and hide sensitive files.