I'm not sure exactly what areas you travel to the most frequently, but I have had great experiences with the Metro. The new Expo line has been such a time saver for me as well as a fun way to sight see, attend events and not have to park. http://www.metro.net/projects/exposition/
"The Metro Expo Line connects the Westside by rail to Downtown LA, Hollywood, the South Bay, Long Beach, Pasadena and dozens of points in between. With 10 new stations serving USC, Expo Park, and diverse LA neighborhoods such as Culver City, the Crenshaw District and Downtown LA, the Metro Rail system will expand to 80 stations and over 87 miles of rail to destinations across LA County."