web application scanning/testing

[fred]

I'll be performing a web assessment soon and have narrowed down a list of tools:
Package    License    URL

Nmap    GPL v2    insecure.org
Paros    Apache License v2    http://www.parosproxy.org/index.shtml
webscarab    Apache License v2    http://www.owasp.org/index.php/Category:OWASP_WebScarab_Project
ProxyStrike    GPL v2    http://www.edge-security.com/proxystrike.php
ratproxy    Apache License v2    http://code.google.com/p/ratproxy/
nikto    GPL v2    www.cirt.net/code/nikto.shtml
ISR-sqlget    GPL v2    http://www.infobyte.com.ar/developments.html
sqlibf    GPL v2    http://www.open-labs.org/
dirb    GPL v2    http://www.open-labs.org/
grendel-scan    Apache License v2    http://www.grendel-scan.com/download.htm

I'm curious to see this last one, was demonstrated at Defcon, but haven't worked with it yet.  Any comments?