Fyodor's list is an excellent resource, one that will repay any time and energy you can devote to it.

The author makes reference to an astounding list of 75 security tools that was listed by Fyodor - author of the indispensible tool NMAP. This is one of the most comprehensive lists I have seen around.

Full article here.

If you want to skip ahead to the list of tools, you can find the them here.

It's a must-have in my book!