I wish I could've gone to some early 90's raves with the oldschool Jungle. I was 8 yrs old when that shit was hot, or maybe Frankie Bones' earliest sets when he first brought raves to the U.S. I've seen Frankie Bones a few times, but like 20 years too late.
As far as jazz, Wes Montgomery is an idol, would love it if I could see him play.
It'd also kick ass to see Bad Brains or DK or Minor Threat in the very very beginning. Another scene I was too young to appreciate at the time that has since gotten pretty lame.
Oh, fuck, I would kill to see Hank Williams Sr. I don't know what his music was like live, cause he became very commercial and I've only heard studio recordings, but it would be incredible to see him when he was starting out playing in some shitty bar.