If you use any *nix OS and you want to secure your system, use nessus. The program more or less hacks the F*** out of your computer with whatever you want it to (it has just about every method of hacking available to test with). Just log on to a virtual server that it creates on your system, choose what you want to throw at yourself, and start the scan. Depending on what all you select it might take a while. Then it gives you this very nice output with plenty of info on everything and you can save it all in a log file of your format choosing (html, txt, etc...). It is like nmap on crack! Get it now:

http://www.nessus.org/nessus_2_0.html