Definitely go to this, got an invite recently - looks like the highest concentration of beautiful hippies the world has ever known. Awesome soundtrack as well.
http://www.youtube.com/watch?v=95jfk624rRs

To get the best out of LA you need to know someone who lives there really (if you'll only be there for a short time) to show you the cool spots - it's so bloody spread out.
SF is great,great, great. Zeitgeist bar is a good spot, Haight-Ashbury district is where the uber cool kids hang out - I would live there but it'd cost me about $4000 a month keeping up with their lightning paced fashion trends.
Castro is a lot of fun if you don't mind astronomical amounts of gayness.
Camp out in Big Sur, stunning.
Pack up your balls and head for Oregon and Washington State - I haven't been but EVERYONE I've met who's been raves about the countryside, progressive cities and general attitudes.