for general purpose vulnerability scanner check out nessus (GPL), Retina (Eeye), etc... for web testing, i would highly recommend whisker. for general purpose firewall testing, check out ftester (0.9) current release. there are number of "tools" you could use at Fyodor's site -> http://www.insecure.org/tools.html . Fyodor is going to be speaking at the next defcon in las vegas.

-w0rm3y