I still don't have much experience in the lines of *nix yet. So my opinions are Windows based.

Firewall - Norton Personal Firewall 2003. I haven't had any conflicts with this, and it hasn't slowed my internet connenction

Antivirus - Panda Antivirus...it's the best, and you can do it free online.

Intrusion Detection - Hmm...Norton does this well, as well as Port Monster 2.0.

Vulnerability Scanner - I would like to have more info on this myself.

Port Scanning - I've only used one before, and it doesn't seem to be too great.

Packet Sniffing - Don't have enough experience to know how these work.

Encryption - ABI Encoder. Choose from several encryption schemes...up to 400-bit encryption. My friend, Lex Luthor, has "f_engima" that also works quite well.

Spam Blocking - Google Toolbar...in all seriousness

Spyware / Adware Blocking or Removal - Ad-Aware 6. That's freeware, correct?

Enumeration Tools - I wouldn't know

Other Miscellaneous Tools - 7zip. Best compression program I've ever seen. Fresh Device's Fresh Download. It's a very nice download manager, and very configurable.