Mandatory Services for Sharepoint (MOSS)

Here are the List of Sharepoint Services which are mandatory on MOSS Farm enviornment
SharePoint Core Services
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+Windows SharePoint Services Web Application
+Windows SharePoint Services Search
+Windows SharePoint Services Incoming E-Mail
+Windows SharePoint Services Outgoing E-Mail
+Windows SharePoint Services Administration
+Windows Sharepoint Services Timer
+Windows Sharepoint Servcies Tracing
+Office SharePoint Server Search
+OfficeDocument Conversions Load Balancer Service
+Office Document Conversions Launcher Service Central Administration
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IIS Core Services
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+IIS Admin Service
+World Wide Web Publishing Service
+SMTP Service (required if using SMTP Service)