I'm a huge believer in legally free stuff. Causes me all kinds of headache at work, as they don't want to use anything for free "because someone might have put a trojan in the source code." Any way, hit
http://www.nessus.org/ for the best security vulnerability available right now (cost - free). You run the scanning engine on a *nix machine. The graphical scanning controller interface runs in *nix and Winderz. When not using Nessus to scan your network, you'll want to routinely run nmap and see what ports are open. Also, Superscan is a great scanner, and is also free (don't have a link handy - you'll have to search for it). It is a Winderz based network vulnerability scanner.
You might also think about running Snort (
http://www.snort.org/) for intrusion detection on your network. Again, it is free, and has plenty of free tools available to make it easier to work with.
ISS is a good scanner, but tasty-hot expensive. And reviews I have seen suggest the ISS is, in the best case, equal to Nessus in detecting vulnerabilities, and in some cases is less capable. ISS has Nessus beat for printing out what it finds and detailing fixes that most non-techies can fix. But for best capabilities, I still say go with Nessus.
Can't help with the database stuff. Let me know if I can help any more.
RagManX