Linda Ronstadt at Berkeley Community Theater, Spring 1975. Roger McGuinn opened for her. I regret to say, though I bought many of her albums, I never saw her again. Such a stunning voice and now, due to Parkinson's, she can't sing. PBS broadcast the Kennedy Center Honors last year where she was recognized and I watched with tears rolling down my cheeks.
Boz Scaggs at The Greek, October '75 before Silk Degrees. He still played tunes from his "Moments" album, my fave. Then saw him in one of his Oakland shows at the Paramount the end of '76 - he'd hit the big time, had an umpteen piece orchestra and the audience was dressed to kill. The next time I saw him was 2006 in Sacramento and I'd just been laid off and needed an emotional lift. It was a hot night, lousy outdoor venue, and he frankly "mailed in" the performance. He was dead to me after that until my wife bought tickets to his show in Folsom last August. It was terrific and restored my faith. Check out Last Tango on 16th Street on YouTube - great song.
Tower of Power - early 2000s at the Gold Country Fair in Auburn. They played in the rodeo arena - great show! Superb, polished musicians.
Junior Walker and the All Stars in Seattle, early 1990s. He showed the ill effects of a musician's life on the road at that point, but he put on a good show and could still blow!
Springsteen - everybody should see him once. He is a force of nature. The way he controls the emotions of the audience is something to behold. You see three generations of fans at his shows, not just Boomers.
On a more mundane level, two Bay Area bands who injected comedy into their shows at local clubs: Butch Whacks and the Glass Packs in the 1970s and The Toons in the 1980s. Lesser-known bands in a small venue can be so much more fun than a big arena show.