Favorite Music Venues?

I went to my first Stern Grove concert a couple of weeks ago and WOW - what a fun experience! Music, sunshine, beer, picnics, happy people everywhere...I can't wait to go back. But that got me thinking...what are some of the other great places to hear music in the city? I went to a concert at AT&T Park last year which was nice just because it is the Ritz-Carlton of baseball stadiums, but surely there are others? Any specific recommendations?