I just finished running the test on my Win2k SP2 system, it found a problem with anonymous users being able to list system info, (though RPC I assume?) a problem with one of my passwords, (too short) and a few missing hot fixes.
Hot Fixes and Service Packs
Password quality (length and strength)
SMB Share security
Local account security
Local service security/status
Overall, it's a pretty nice tool that can help keep Microsoft systems up-to-date, since obviously everyone is having a hard time doing so. (including Microsoft) I'll be curious to hear from everyone how bad or good their system faired.
Microsoft Personal Security Advisor