http://www.securityspace.com

Securityspace has 2032 vunerability tests in 22 catagories, and adds more every week.

CGI abuses
Denial of Service
Windows
General
Gain root remotely
Misc.
FTP
RPC
Remote file access
Backdoors
Gain a shell remotely
SMTP problems
CISCO
Windows User Mngmnt
Useless services
Firewalls
SNMP
Untested
Finger abuses
Settings
Port scanners
NIS

Audited devices:

Web servers
Routers
FTP servers
Operating Systems
Load Balancing servers
Firewalls
Databases
LDAP servers
hubs & switches
E-Commerce applications

Other sites available:
http://www.sdesign.com/securitytest/ http://www.it-sec.de/vulchke.html http://www.cablemodemhelp.com/portscan.htm
http://www.mycgiserver.com/servlet/kalish.Security
http://www.pcflank.com/