"...I've noticed that SQL Server 2000 services can be set with to run under a groupless user account with minimal permissions (the configuration wizard sets the permissions on resources that are required). What are minimum privileges required for each component of MOM and SMS to run properly in a similar manner?..."
- MOM has this documented in the "Security Guide" for online reading. Specifically in this chapter.
- SMS has it documented in "Scenarios and Procedures for Microsoft Systems Management Server 2003: Security". I recommend reading the Security section in its entirety as it contains not only service permissions discussions, but more wholistic security issues too relating to SMS 2003.