Both accessed from the Metro Express 761 route:
Pictures from the Getty Museum will give you a good overview of Santa Monica & Century City and points South.
Pictures from the Mulholland Bridge over I-405 (right by the Skirball Museum) will give you a great view of the Central San Fernando Valley.
Griffith Observatory has *weekend* (Sa & Su) shuttle service from 10 am to 10 p.m. from the Vermont/Sunset Metro Red Line station. The view will get you sights of the LA basin South including Downtown, Hollywood, etc.