1) Avast Antivirus - One of the best antivirus we like. Free for home use. Really worth upgrading to commercial edition.
2) Comodo Firewall - Good personal Firewall.
3) CutePDF - Do you want a fast and easy way to create PDF documents? Try this.
4) MagicDisc - A great tool which can be used as a virtual drive to mount image files (*.iso, *.bin etc).
5) Wireshark - Worlds leading Network Protocol Analyser.
6) Nmap - Free Security Scanner
7) Knoppix - Linux Live Boot CD