I won't weigh in on the best live album because my tastes are so varied now that i can't say anymore, but AB live at filmore is a sweet album. My favorite song has to be stormy monday . I have always love a particular part of stormy monday when Duane plays that simple little riff at about 2:50 of the song right after greg sings lord have mercy after which someone in the crowd lets out a yell. to me that little riff is the best part of the whole album. Still gives me a rush when I hear it for the 1000th time.
I also really respect duane more now as I recently read one of his favorite albums to listen to was Kind of Blue, miles davis, which i also love.